Lakhmir Singh Class 10 Chemistry 3rd Chapter Metals and Non – metals Solution

Lakhmir Singh Class 10 Chemistry 3rd Chapter Metals and non- metals Solution

 

Lakhmir Singh Manjit Kaur Chemistry Solution: Metals and non- metals Chapter 3. Here you get easy Solutions of Lakhmir Singh Class 10 Chemistry Solution Chapter 3. Here we have given Chapter 3 all Solution of Class 10. Its help you to complete your homework.

  • Board – CBSE
  • Text Book – Chemistry
  • Class – 10
  • Chapter – 03

 

Lakhmir Singh Class 10 Chemistry 3rd Chapter Solution

 

Very short question answer

 

1.) Name one metal and non metal which exist in liquid state at room temperature.

Ans : The mercury metal which exist in liquid state at room temperature and the bromine is non metal which exist in liquid stateat room temperature.

 

2.) Why are metals called electropositive elements whereas non-metals are called electronegative elements?

Ans :

  • Metals are electropositive because metals donate the electron and positive ion is formed to achieve stability.
  • Non metals are electronegative because they accept the electron and form negative ion.

3.(A) Name the most abundant metal in the earth’s crust.

Ans: Aluminium is most abundant metal in earth’s crust.

(B) Name the most abundant non-metal in the earth’s crust.

Ans : oxygen is most abundant non-metal in earth’s crust.

4.) Name one metal which has a low melting point.

Ans : Caesium metal which has a low melting point that is 28°C because due to large size interatomic bond weak.

5.) Name the metal which is the poorest conductor of heat.

Ans: lead is poorest conductor of heat and electricity because when metal exposed to heat and the gain of energy takes place this energy transfer to another atom but in case of lead heat is not transfer to another atom therefore it is poor conductor of heat.

6.) state whether the following statement is true or false :

Non metals react with dilute acid to produce a gas which burns with a ‘pop’ sound.

Answer : Non metals react with dilute acid to produce a gas which burns with a ‘pop’ sound this sentence is false because non metal not react with dilute acid.

7.) From amongst the metals sodium, calcium, aluminium, copper, and magnesium name the metal :

(i) which react with water only on boiling

Ans: Magnesium react with water only on boiling and form magnesium hydroxide

Mg(s) + 2H2O(l) —> Mg (OH)2(aq) + H2(g)

(ii) another which does not react even with steam.

Ans : Calcium and magnesium not react with steam but react with water

8.) what changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution for about 30 minutes?

9.) what is Aqua-regia? Name two special metals which are insoluble in common regents but dissolve in aqua – regia.

Ans : The mixture of concentrated nitric acid and concentrated Hydrochloric acid with 1:3 ratio is called Aqua-regia. Gold and Platinum which are dissolve in aqua-regia because aqua-regia is highly corrosive.

10. Give the name of names and formulae of (a) two acids oxides, and (b) two basic oxides.

Ans: (a) carbon dioxide and sulphur dioxide are acidic oxide.

(b) Sodium oxide and magnesium dioxide are basic oxide

11.) What name is given to those metal oxides which show basic as well as acidic behaviour.

Ans: The metal oxide as ZnO, Al2O3 which show basic as well as acidic behaviour and it is also called Amphoteric oxide.

12. Name two metal which from Amphoteric oxide.

Ans: ZnO and Al2O3 which are amphoteric oxide because they show basic as well as acidic behaviour

13.) A copper coin Is kept immersed In solution of Silver nitrate For some time. What will happen to the coin and colour Of the solution.

Ans: when copper coin kept in solution of silver nitrate after some time the color of copper coin change it appear as shiny white colour because copper more reactive than silver and due to silver deposition shiny white colour appear and colour of solution become blue.

14.) which property of copper and aluminium makes them suitable:

(a) for making cooking utensil and boilers

Ans: Copper and Aluminium are god conductor of heat and show high thermal conductivity therefore and Copper and Aluminium use for making cooking utensil and boilers.

(b) for making electric wires

Ans: Copper and Aluminium have low electric resistance and good conductor of electricity and easy flow of electric current.

15.) Write the names and formulae of

(a) a metal hydride

Ans: Calcium react with hydrogen form calcium hydride

2 Ca(s) + O2(g) ——> 2 CaO(s)

(b) a non metal hydride

Ans: sulphur is react with hydrogen it form hydrogen sulphide

H2(g) + S(l) ⟶ H2S

16. Metal which has been placed :

 

(a) at the bottom of reactivity series

Ans: In electrochemical series down the group chemical reactivity decreases.

K>Na>Ca>Mg>Al>Zn>Fe>Sn>H>Cu>Hg>Ag>Au

according to these bottom of reactivity series Cu> Hg>Ag>Au and all 3 metals least reactive

 

(b) at the top of the reactivity series.

Ans: According to reactivity series some metals are situated at top position those metals are more reactive.

The top of the reactivity series is K>Na>Ca>Mg>Al>Zn>Fe>Sn

 

(C) Just below copper in reactivity series.

Ans: Copper is situated blow position according to reactivity series because it is least reactive than hydrogen and does not react with water and acid to form hydrogen gas.

17] which of the two metal is more reactive : copper or silver ?

Ans : Copper is more reactive than silver because according to periodic table top to bottom Electronegativity decrease and therefore copper is Electronegative than silver easily loss electron

18.a) Name one metal which stored under water.

Ans : No any metal which stored in water because some metal are exposed to water and some metals easily react with water.

 

(b) Name one non-metal which is stored under water.
Ans: Phosphorus stored in water because phosphorus metal is more reactive those are catch fire with atmospheric air.

 

18.a)  Name one metal which stored under water.

Ans : No any metal which stored in water because some metal are exposed to water and some metals easily react with water.

 

(b) Name one non-metal which is stored under water.

Ans: Phosphorus stored in water because phosphorus metal is more reactive those are catch fire with atmospheric air.

 

19. write equation for the reaction of :

(a) sodium with oxygen

Ans: When at room temperature solid state sodium react with oxygen in air it form sodium oxide and it is basic oxide.

4Na (s) + O2(g) → 2 Na2O(s)

Sodium + Oxygen  → sodium oxide

 

(b) magnesium with oxygen

Ans: On heating condition Magnesium metal react with oxygen and form magnesium oxide.

2Mg(s)+   O2(g)   →     2MgO(s)

       Magnesium  +  Oxygen  →   Magnesium Oxide

 

20.) Names two metals which are used :

(a) for making electric wires.
Ans: Copper and Aluminium both metals are use in electric wire because they are ductile and are thermal resistant therefore easily flow of electric current.

(b) for making domestic utensils and factory equipment.
Ans: aluminium and copper are use for making domestic utensils and factory equipment.

(C) For making jewellery and to decorate sweets.
Ans: gold and silver are use for making jewellery because they are highly malleable , ductile , lustrous and less reactive and gold and silver foil use to decorate sweets does not affect on human health.

21.) Which metal foil is used for packing some of medicines tablets ?

Ans : Aluminium metal foil is used for packing of medicines tablets.

22. Name the non metal which is used :

(a) to convert the vegetable oil into vegetable ghee (solid fat).

Ans: In gaseous form hydrogen is use for vegetable oil convert into vegetable ghee.

(b) as a rocket fuel (in liquid form)

Ans: Liquid hydrogen use in rocket fuel.

(C) to preserve food material.

Ans: Nitrogen use for preserve food material because it show inertness property.

(d) in the Vulcanisation of rubber.

Ans: Sulphur non metal use in the Vulcanisation of rubber.

23.) Name one property which is characteristic of

Ans:(a) metal → metals are malleable and ductile.

Ans:(b) non-metal → non metals are not malleable or ductile, they are brittle.

24.) What is mean by “brittleness”? Which type of elements usually show brittleness

Ans: Brittleness is the property of substance those are easily break and not show deformation. P block elements show brittleness.

 

25.) What will happen if strip of zinc is immersed in a solution of copper sulphate?

Ans: CuSO4 (aq) + Zn (s) → ZnSO4ZnSO4(aq) + Cu (s)

when strip of zinc is immersed in copper sulphate solution the blue color of copper sulphate solution disappear due to formation of colourless zinc sulphate and red brown color coating of copper on zinc Strip.

26.) What happens if a strip of copper is kept immersed in a solution of silver nitrate (AgNO3) ?

Ans: Cu (s) + AgNO3(aq) →Cu(NO3) + 2Ag

When copper react with silver nitrate solution copper displaced from silver nitrate solution and blue colure solution form and it is displacement reaction.

 

27.) What happens when iron nails are put on copper sulphate solution?

Ans: when iron nails are put on copper sulphate solution,brown colour coating of copper is formed on surface of iron and copper sulphate solution colour change blue to light green. In this reaction iron is more reactive than copper and iron displace copper in copper sulphate solution hence chemical changes occurs.

Fe (s) + CuSO4 → Cu(s) + FeSO4

 

28.) Why would you show that silver is chemically less reactive than copper?

Ans: In periodic table down the group chemical reactivity decreases and silver not easily give valence electron for reactivity hence silver less reactive than copper.
silver is less reactive than copper because in chemical reactivity series silver place at bottom and reactivity decrease in bottom side.

 

29.) Give reason for the following :

Blue colour copper solution is destroyed when iron filing are it

Ans: when iron filling immersed in copper solution the blue colour of copper solution destroyed because iron is more reactive than copper and iron displaced copper.

 

30.) Name a non metal having high melting point.

Ans: diamond have high melting point.

 

31.) Which property of graphite is utilised in making electrodes ?

Ans: graphite is good conductor of electricity hence graphite is utilised in making electrodes.

32.) Name two non-metals which are both brittle and non-ductile.

Ans: phosphorus and sulphur both non-metal which are brittle and non-metal.

 

33.) Explain why the surface of some metals acquires a dull appearance when exposed to air for a long time?

Ans: Some metals are react with oxygen and metal oxide form. Due to formation of metal oxide the surface of some metals acquires a dull appearance when exposed to air.

 

34. Complete and balance the following equations :

(a) Na + O2 ———- H2O

Ans: 4Na(s) + O2(g) →2Na20 (s)

(b) Na2O+H2O ———— H2O

Ans : Na2O(s) + H2O(l) → 2NaOH(aq)

(c) Fe (s) + H2O (g) →

Ans: 3Fe (s) + 4H2O (g) →Fe3O4(s) + 4H2(g)

(d) Cu(NO3)2 (aq) + Zn (s) H2O

 

35. Fill in the following blanks with suitable words :

(a)  Ans: Magnesium liberates hydrogen gas on reacting with hot boiling water.

(b) Ans: The white powder formed when magnesium ribbon burns in oxygen is of magnesium oxide

(c) Ans: Ordinary aluminium strips are not attacked by water because of the presence of a layer of aluminium oxide on the surface of aluminium.

(d)  Ans-  A metal having low melting point issodium but a non-metal having very high melting point is diamond

(e) Ans: Calcium is a less reactive metal than sodium.

 

36. (a) What is meant by saying that the metals are malleable and ductile ? Explain with examples.

Ans: malleable and ductile means to give shape of metal without braking or cracking. The example is silver. Silver metal possess malleable and ductile property and is use for jewellery.

 

(b) Name two metals which are both malleable and ductile.

Ans: Copper and platinum metals are both malleable and ductile.

 

(c) Which property of iron metal is utilised in producing iron sheets required for making buckets ?

Ans: Malleability property of iron metals is utilised in producing iron sheets required for making buckets.
(d) Which property of copper metal is utilised in making thin wires ?
Ans: Ductility this property of copper metal is utilised in making things wires.

 

37.) Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction ?

Ans: Sodium and Potassium which react violently with cold water. Three observation make when such metal is dropped into water

  • 1. Due to small explosion metals move on surface of water
  • 2. Metals are catch fire
  • 3. Metals start burning

During the reaction the gas burns producing the pop sound indicating that it is hydrogen.

 

38.
(a) With the help of examples, describe how metal oxides differ from non-metal oxides.

Ans :

                     Metal oxide                      Non metal oxide
Metal oxides are chemical compound a metal and one or more oxygen atoms.

Foe example. Magnesium metal react with oxygen magnesium dioxide form.

2Mg(s) +O2(g) →2MgO(s)

Nonmetal oxides are oxide compounds formed by nonmetal elements.

Foe example. sulfur nonmetal react with oxygen to form sulfur dioxide.

S(s) + O2(g) → SO2(g)


 

(b) Which of the following elements would yield : (i) an acidic oxide, (ii) a basic oxide, and (iii) a neutral oxide ?
Na, S, C, K, H

Ans : An acidic oxide – S and C
Basic oxide –Na and K
Neutral oxide – H

 

39. (a) What are amphoteric oxides ? Give two examples of amphoteric oxides.

Ans: Metal Oxide react with acid and base and form salt and water.
Example of amphoteric oxides are zinc oxide and aluminium oxide.

 

(b) Choose the acidic oxides, basic oxides and neutral oxides from the following : Na2O ; CO2 ; CO ; SO2 ; MgO ; N2O ; H2O.

Ans: Acidic Oxide – CO2 and SO2
Basic oxide – Na2O and MgO
Neutral oxide – N2O, H2O and CO

 

(c) Which of the following are amphoteric oxides : MgO, ZnO, P2O3, Al2O3, NO2

Ans: Amphoteric oxides are ZnO and Al2O3

40. (a) What is the nature of the oxide SO2 ? What happens when it is dissolved in water ? Write the chemical equation of the reaction involved.

Ans: nature of the oxide SO2 is acidic.

When the gaseous form sulphur dioxide (SO2) react with water (H2O) ,sulphuric acid form and it is acidic in nature.

The chemical equation of the reaction involved is SO2+ H2O → H2SO3

 

(b) What is the nature of the oxide Na2O ? What happens when it is dissolved in water ? Write the chemical equation of the reaction involved.

Ans: Nature of the oxide Na2O is basic. When sodium oxide (Na2O) react with water (H2O) ,the sodium hydroxide(NaOH) form

The chemical reaction – Na2O + H2O → 2NaOH

 

41. (a) What type of oxides are formed when non-metals react with oxygen ? Explain with an example.

Ans: Both acidic oxide or neutral oxide formed when non metal react with oxygen. When sulphur non-metal react with oxygen, sulphur dioxide form and it is acidic in nature.

S(s) + O2(g) → SO2(g)

 

(b) What type of oxides are formed when metals combine with oxygen ? Explain with the help of an example.

Ans: Basic oxide formed when metal react with oxygen. When Magnesium metal react with oxygen magnesium dioxide formed.

2Mg(s) +O2(g) →2MgO(s)

 

42. (a) Explain why, metals usually do not liberate hydrogen gas with dilute nitric acid.

Ans: Metals usually do not liberate hydrogen gas with dilute nitric acid because nitric acid is strong oxidizing agent hence hydrogen gas not evolved when metal react with nitric acid.

(b) Name two metals which can, however, liberate hydrogen gas from very dilute nitric acid.

Ans:- Magnesium and Manganese both are liberate hydrogen gas from very dilute nitric acid.

43. (a) How do metals react with hydrogen ? Explain with an example.

Ans:- Generally metals not react with hydrogen but some reactive metals sodium, potassium, calcium react with hydrogen and form meatal hydride. For example. Sodium lose electron and hydrogen accept the electron from sodium and form sodium hydride

2Na + H2 → 2NaH

(b) How do non-metals react with hydrogen ? Explain with an example.

Ans: Non metal react with hydrogen. When non metal react with hydrogen the covalent bond form between metal and hydrogen. For example: Sulphur non metal react with hydrogen the covalent bond from between hydrogen and sulphur because sulphur share valance electron with hydrogen and form sulphur and it is covalent in nature.

H2 + S → H2S.

44.(a) What happens when calcium reacts with chlorine ? Write an equation for the reaction which takes place.

Ans: when calcium react with chlorine form calcium chloride and it is ionic in nature.

Ca + Cl2 → Cacl2

 

(b) What happens when magnesium reacts with very dilute nitric acid ? Write an equation for the reaction involved.

Ans: when magnesium react with dilute nitric acid form magnesium nitrateit is salt and hydrogen gas evolved.

2 Mg + 2HNO3 → 2 MgNO3 +H2

45.(a) Arrange the following metals in order of their chemical reactivity, placing the most reactive metal first : Magnesium, Copper, Iron, Sodium, Zinc, Lead, Calcium.

Ans: according to chemical reactivity order of metals

Sodium>lithium>Calcium>Magnesium>Aluminium>zinc>Iron>lead>Copper.

 

b) What happens when a rod of zinc metal is dipped into a solution of copper sulphate ? Give chemical equation of the reaction involved.

Ans: when a rod of zinc metal dipped into copper sulphate solution, zinc displaces copper in the solution.

Chemical equation – Zn + CuSO4 → ZnSO4 + Cu.

46.) A copper plate was dipped in AgNO3 solution. After certain time, silver from the solution was deposited on the copper plate. State the reason why it happened. Give the chemical equation of the reaction involved.

Ans. Copper plate was dipped in AgNO3 solutions , the silver deposited on the copper plate because copper more reactive than silver and hence copper displaces from silver from the silver nitrate solution.

Cu + AgNO3 → Cu(NO3)2 + 2Ag

47. State five uses of metals and five of non-metals.

Ans: The five uses of metals are following –

  • 1. Metals are use for carry electric conductor.
  • 2. Metals are use for galvanizing process for rusting of iron.eg. Zinc
  • 3. Metals are useful for making jewellery and food packing sheet. eg. Platinum, Gold, silver.
  • 4. Metals are use in making car batteries.
  • 5. Mercury metal use in thermometer.

The five uses of non metals are following –

  • 1. Non-metal use for fertilizer. eg. Sulphur, Nitrogen
  • 2. Non-metal use for breathing by living organisms. eg. Oxygen
  • 3. Non-metal use as racket fuel. eg. Hydrogen
  • 4. Non-metal use in purification of water. eg. Chlorine
  • 5. Non-metal use in pencil fillers.eg. Graphite

48. State one use each of the following metals : Copper, Aluminium, Iron, Silver, Gold, Mercury

Ans: Uses of metals :

  • 1. Copper –Copper wire use for electric wire for carry electric conductor.
  • 2. Aluminium – aluminium foil use for packing food
  • 3. Iron –Iron useful for making cooking utensils.
  • 4. Silver – silver is useful for making jewellery.
  • 5. Good – Gold also useful for making jewellery.
  • 6. Mercury –mercury use in thermometer.

49. (a) State one use each of the following non-metals : Hydrogen, Carbon (as Graphite), Nitrogen, Sulphur

Ans: use of non-metal :

  • 1. Hydrogen : Hydrogen use for racket fuel.
  • 2. Carbon (as graphite) : graphite use inpencil filler.
  • 3. Nitrogen :Nitrogen used by plant.
  • 4. Sulphur : sulphur are use for fertilizer.

(b) Name the metal which is used in making thermometers.

Ans: Mercury metal is liquid form and used in making thermometer.

50. (a) Why does aluminium not react with water under ordinary conditions ?

Ans : Aluminium not react with water under ordinary conditions because in presence of water aluminium oxide form and thin layer of aluminium oxideon its surface.

 

(b) Name two metals which can displace hydrogen from dilute acids.

Ans: Sodium and Magnesium can displace hydrogen from dilute acids.

 

(c) Name two metals which cannot displace hydrogen from dilute acids.

Ans: Copper and zinc cannot displace hydrogen from dilute acids.

51. (a) Why is sodium kept immersed in kerosene oil ?

Ans: when sodium contact with water it catch fire. It is highly explosive in water therefore sodium kept in kerosene oil.

 

(b) Why is white phosphorus kept immersed under water ?

Ans: phosphorus is highly explosive with air therefore phosphorus kept immersed under water.

 

(c) Can we keep sodium immersed under water ? Why ?
Ans: No sodium not immersed in water because sodium highly reactive with water and catch fire.

52. (a) Describe the reaction of potassium with water. Write the equation of the reaction involved.

Ans: Potassium react harshly with water to form potassium hydroxide and heat also generate.

2K + 2H2O → 2KOH + H2

 

(b) Write an equation of the reaction of iron with steam. Indicate the physical states of all the reactants and products.

Ans: solid state of iron metal react with water steam to form iron oxide in aqueous medium and hydrogen gas evolved.

3Fe(s) + 4H2O(g) → Fe3O4(aq) + 4H2(g)

(c) Which gas is produced when dilute hydrochloric acid is added to a reactive metal ?

Ans: Hydrogen gad produced when dilute hydrochloric acid is added to a reactive metal.

53. (a) Give one example, with equation, of the displacement of hydrogen by a metal from an acid.

Ans: Magnesium react with dilute nitric acid to form magnesium nitrate and hydrogen gas.

Mg + HNO3 → Mg(NO3) 2 + H2

 

(b) Name two metals (other than zinc and iron) which can displace hydrogen from dilute hydrochloric acid ?

Ans: Aluminium and calcium which can displace hydrogen from dilute hydrochloric acid.

 

54. What is the action of water on (a) sodium (b) magnesium, and (c) aluminium ? Write equations of the chemical reactions involved.

Ans:

1.Sodium – sodium react with water form sodium hydroxide and hydrogen gas evolved.

2Na(s) + H2O (l) → 2NaOH(aq) + H2(g)

 

2. Magnesium –Magnesium react with water to form magnesium hydroxide.

Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g)

 

3.Aluminium – aluminium react with water to form aluminium oxide.

2Al(s) + 3H2O(l) →Al2O3(s) + 3H2(g)

 

55. You are given samples of three metals — sodium, magnesium and copper. Suggest any two activities to arrange them in order of their decreasing reactivates.

Ans: a) sodium – sodium react with oxygen to from sodium oxide.

Na + O2 → Na2O

b) magnesium react with oxygen on heating

Mg + O2 → MgO

C) copper not react with oxygen s

Cu + O2 → no reaction

Sodium is more reactive metal and copper least reactive therefore order of their decreasing reactivity is sodium > magnesium >copper.

56. (a) Write one reaction in which aluminium oxide behaves as a basic oxide and another in which it behaves as an acidic oxide.

Ans: Al2O3(S) + 6HCl(aq) → 2AlCl3(aq) + 3H2O(l)

In this reaction in which aluminium oxide basic oxide because it react with hydrochloric acid to form aluminium salt and water.

Al2O3(S) + 2NaOH(aq) → 2NaAlO2 (aq) + H2O(l)

In this reaction in which aluminium oxide acidic oxide because it react with sodium hydroxide to form sodium aluminate salt and water.

(b) What special name is given to substances like aluminium oxide.

Ans: Amphoteric oxides substances like aluminium oxide.

(c) Name another metal oxide which behaves like aluminium oxide.

Ans: metal oxide which behaves like aluminium oxide is zinc oxide.

57. (a) What happens when calcium reacts with water ? Write the chemical equation of the reaction of calcium with water.

Ans: Calcium metal reacts with water from calcium hydroxide and hydrogen gas.

Ca(s) + H2O (l) → Ca(OH)2(aq) + H2(g)

 

(b) Write the chemical equation of the reaction which takes place when iron reacts with dilute sulphuric acid. What happens when the gas produced is ignited with a burning matchstick ?

Ans:chemical equation of the reaction between iron reacts and dilute sulphuric acid is as follow

Fe(s) + H2SO4(aq) → FeSO4(aq) + H2(g)

58. You are given a dry cell, a torch bulb with holder, wires and crocodile clips. How would you use them to distinguish between samples of metals and non-metals ?

Ans: we know metals are good conductor electricity and easy carry currents suppose copper metal use in torch bulb with holder wires and crocodile clips copper current and bulb will be light up. and sulphur non metal use in torch bulb with holder wires and crocodile clips copper current and bulb will not light up because non metal bad conductor of electricity no carry current.

59. State any five physical properties of metals and five physical properties of non-metals.

Ans: Five physical properties of metals are following

  • 1. Metals are malleable and ductile.
  • 2. Metals are good conductor of heat and electricity.
  • 3. Metals form basic oxides.
  • 4. Metals are electropositive in nature.
  • 5. Metals form unstable hydrides.

Five physical properties of non-metals are following

  • 1. Metals are not malleable and ductile.
  • 2. Metals are bad conductor of heat and electricity.
  • 3. Metals form acidic oxides.
  • 4. Metals are electronegative in nature.
  • 5. Metals form stable hydrides.

60. (a) Name two physical properties each of sodium and carbon in which their behaviour is not as expected from their classification as metal and non-metal respectively.

Ans:

(b) Name two metals whose melting points are so low that they melt when held in the hand.

Ans:

 

61.) Metals are said to be shiny. Why do metals generally appear to be dull ? How can their brightness be restored ?

Ans: . Metals are said to be shiny but after some times they appear to be dull because when metal exposed with oxygen in air form oxides for these formation of dull thin layer for oxides. The metals are corrode bur they are rubbing with sand paper their brightness restored.

 

Long Answer Type Questions

 

62.
(a) What are metals ? Name five metals.

Ans: Those substances have hard, shiny, which conduct heat and electricity and they are malleable, ductile is called metal. The examples of metal are copper, aluminium, iron, gold, platinum.

 

(b) Name a metal which is so soft that it can be cut with a knife.

Ans: sodium metal which is so soft that it can be cut with a knife.

 

(c) Name the metal which is the best conductor of heat and electricity.

Ans: copper metal best conductor pf heat and electricity.

 

(d) What happens when a metal reacts with dilute hydrochloric acid ? Explain with the help of an example.

Ans: when a metal reacts with dilute hydrochloric acid , the metal salt and hydrogen gas form.

For example. Sodium metal react with hydrochloric acid the sodium chloride salt form
2Na + HCl → Nacl

 

(e) Write the equations for the reactions of and Name the products formed in each case. Also indicate the physical states of all the substances involved.

(i) Magnesium with dilute hydrochloric acid

Ans: Mg(s)+ 2HCl(aq) → Mgcl2(aq) + H2(g)

Magnesium with dilute hydrochloric acid the product form a Magnesium chloride

 

(ii) Aluminium with dilute hydrochloric acid

Ans 2Al(s)+ 6HC(aq)l → 2AlCl3 + 3H2(g)

Aluminium with dilute hydrochloric acid the product form Aluminium chloride

 

(iii) Zinc with dilute hydrochloric acid

Ans: Zn(s) + 2HCl(aq) → ZnCl2+H2(g)

Zinc with dilute hydrochloric the product form Zinc chloride

 

(iv) Iron with dilute hydrochloric acid

Ans: Fe(s)+ 2HCl(aq) →FeCl2

iron with dilute hydrochloric acid the product form Iron chloride

63. (a) Define non-metals. Give five examples of non-metals.

Ans: The elements that are bad conductor of heat and electricity, they are not malleable and ductile lustre is called non metal.

The examples of non-metals are Carbon, Sulphur, phosphorus, Nitrogen, chlorine.

 

(b) Name a non-metal which conducts electricity.

Ans: non-metal which conducts electricity is aluminium.

 

(c) Name a non-metal having lustre (shining surface).

Ans: iodine non-metal having lustre.

 

(d) Name a non-metal which is extremely hard.

Ans: diamond non-metal which is extremely hard.

 

(e) How do non-metals react with oxygen ? Explain with an example. Give equation of the reaction involved. What is the nature of the product formed ? How will you demonstrate it ?

Ans: when non metal react with oxygen form acidic or neutral oxides and it is always covalent in nature and share of electrons.

For example – non metal nitrogen react with oxygen the nitric oxide form.

N2 + O2 → 2NO

The product formed nitric oxide it is acidic in nature.
Demonstration – nitric oxide gas dissolve in water the hydrogen ion release.in this solution deep blue litmus paper ,the blue litmus paper turn to red. For this observation nitric oxide acidic in nature .

 

64 )

(a) What is meant by the reactivity series of metals ? Arrange the following metals in an increasing order of their reactivities towards water : Zinc, Iron, Magnesium, Sodium

Ans: The reactivity series of metal means the metals are in their reactivity order the more reactive metals are placed at top position in series and they have more tendency to lose electron but less reactive metal placed bottom position because less tendency to loss of electron is called reactivity series of metals.

K >Na > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au

 

Metals in an increasing order of their reactivities towards water : Zinc, Iron, Magnesium, Sodium

Iron < zinc < magnesium < sodium.

(b) Hydrogen is not a metal but still it has been assigned a place in the reactivity series of metals. Why ?

Ans: Hydrogen is not a metal but it is loss of electron and form H+ ion and hence it is assigned in the reactivity series of metal.

(c) Name one metal more reactive and another less reactive than hydrogen.

Ans: zinc metal more reactive and copper less reactive than hydrogen.

 

( d )Name one metal which displaces copper from copper sulphate solution and one which does not.

Ans: Zinc metal displace copper from copper sulphate solution and mercury metal which does not.

e) Name one metal which displaces silver from silver nitrate solution and one which does not.

Ans: Copper metal which displaces silver from silver nitrate solution and gold metal which does not.

 

65) (a) State any three differences between the physical properties of metals and non-metal.

 

Metals 

Non metals

1.)metals have lustre 1.)non metal not lustrous
2.)metal have malleable 2.)non metal are not malleable
3.)metal have high density 3.)non metal have low density.

 

(b) Differentiate between metals and non-metals on the basis of their chemical properties.

Ans:      

Metal

Non metal

1.) metals are good reducing agent. 1.) Non metals are good oxidising agent
2.) metal oxides are basic in nature. 2.) Non-metal oxide are acidic in nature.
3.) metal are form unstable hydride. 3.) Non metals are form stable hydride.

 

(c) State three reasons (of which at least one must be chemical) for believing that sodium is a metal.

Ans:

  • Sodium contain one electron in valance shell.
  • Sodium soft and shiny metal.
  • Sodium metal good conductor of heat and electricity.

(d ) State three reasons (of which at least one must be chemical) for believing that sulphur is a non-metal.

( e ) Which non-metal has been placed in the reactivity series of metals ?

 

Part 2 Solution

 

Very Short Answer Type Questions

1. What is the name of the chemical bond

(a) formed by the sharing of electrons between two atoms .

Ans. Covalent bond formed by the sharing of electrons between two atoms .

 

(b) formed by the transfer of electrons from one atom to another ?
Ans: ionic bond formed by the transfer of electrons from one atom to another.

2. Name a carbon containing molecule which has two double bonds.

Ans: Carbon dioxide is carbon containing molecule which has two double bonds

 

3. What would be the electron-dot structure of carbon dioxide which has the formula CO2 ?

Ans: In which 2 oxygen atoms and one carbon atom is present. The valence electron of oxygen is 6.The carbon have ability of sharing the 4 valence electrons with the oxygen atoms. Thereforedouble bond between oxygen and carbon.

4.What type of chemical bond is formed between : (a) potassium and bromine ? (b) carbon and bromine ?

Ans. (a) potassium and bromine –The chemical bond formed between potassium and bromine is ionic bond.

(b) Carbon and bromine – The chemical bond formed between carbon and bromine is covalent bond.

5.
(a) What do we call those particles which have more or less electrons than the normal atoms ?
Ans. Ions particles which have more or less electrons than the normal atoms.

(b) What do we call those particles which have more electrons than the normal atoms ?

Ans. Those particles which have more electrons than the normal atoms are called as anions

(b) What do we call those particles which have less electrons than the normal atoms ?

Ans. Those particles which have less electrons than the normal atoms is called ion.

6.)
(a) The atomic number of sodium is 11. What is the number of electrons in Na+ ?

Ans: atomic number of sodium is 11 and donate one electron the number of electrons in Na+ are 10.

(b) The atomic number of chlorine is

Ans: Atomic number of chlorine is 17.

 

7.) The atomic number of an element X is 8 and that of element Y is 12. Write down the symbols of the ions you would expect to be formed from their atoms.

Ans: symbol of element those atomic number 8 – O
Symbol of elements those atomic number 12 –

8.(a) Write down the electronic configuration of (i) magnesium atom, and (ii) magnesium ion. (At. No. of Mg = 12)

Ans: I) Electronic configuration of magnesium atom – Mg → 2, 8, 2

II) Electronic configuration of magnesium ion – Mg2+ → 2, 8

(b) Write down the electronic configuration of (i) sulphur atom, and (ii) sulphide ion. (At. No. of S = 16)

Ans: Electronic configuration of sulphur atom– S → 2,8,6
Electronic configuration of sulphide ion -S2- → 2,8,8

 

9. What type of chemical bonds are present in a solid compound which has a high melting point, does not conduct electricity in the solid state but becomes a good conductor in the molten state ?

Ans: Ionic bond present in solid compound which has a high melting point, does not conduct electricity in the solid state but become a good conductor in the molten state.

 

10. State whether the following statement is true or false : The aqueous solution of an ionic compound conducts electricity because there are plenty of free electrons in the solution.

Ans: The statement is false : The aqueous solution of an ionic compound contain electricity because there are plenty of free ionin the solution.

 

11. What type of bonds are present in hydrogen chloride and oxygen ?

Ans: In hydrogen chloride covalent bond present because hydrogen share one electron with chlorine electron and form covalent bond.

H2 +Cl2 → 2HCl

 

12. Write the electron-dot structures for the following molecules : (i) NaCl (ii) Cl2

 

Electron structure of NaCl –

 

Electron dot structure of Cl2 –

 

13) What type of bonds are present in water molecule ? Draw the electron-dot structure of water (H2O).

Covalent bond present in water molecule

 

14) What type of bonds are present in methane (CH4) and sodium chloride (NaCl) ?

Ans: In methane(CH4) covalent bond present. In sodium chloride (NaCl) ionic bond present.

 

15) State one major difference between covalent and ionic bonds and give one example each of covalent and ionic compounds.

Ans:     

               Covalent bond

                     Ionic bond

Covalent bond is weak bond. Ionic bond is strong bond
Methane. (CH4) Sodium chloride (Nacl)

 

16) What type of bonds are present in the following molecules ? Draw their electron-dot structures. (i) H2 (ii) CH4 (iii) Cl2 (iv) O2 17. Which inert gas electron configuration do the Cl atoms in Cl2 molecule resemble ? What is this electron configuration ?

Ans: i) H2 –  in H2 molecule covalent bond present.

 

ii) CH4 molecule in which covalent bond present.

 

iii) Cl2 molecule in which covalent bond present.

 

iv) O2 – in O2 molecule

 

18. Which of the following compounds are ionic and which are covalent ? Urea, Cane sugar, Hydrogen chloride, Sodium chloride, Ammonium chloride, Carbon tetrachloride, Ammonia, Alcohol, Magnesium chloride.

Ans: The ionic compounds are Sodium chloride, ammonium chloride, Magnesium chloride.

The covalent compounds are urea, Cane sugar, hydrogen chloride, carbon tetrachloride,

19. Give one example each of the following :

(i) A molecule containing a single covalent bond

Ans. Hydrogen containing a single covalent bond.

 

(ii) A molecule containing a double covalent bond

Ans. Oxygen containing a double covalent bond .

 

(iii) A molecule containing a triple covalent bond

Ans. Nitrogen containing a triple covalent bond.

 

(iv) A compound containing an ionic bond:

Ans. Compound containing an ionic bond Sodium Chloride.

Fill in the blanks in the following sentences :

1. Ans. Two atoms of the same element combine to form a molecule. The bond between them is known as covalent bond.

2.Ans. Two chlorine atoms combine to form a molecule. The bond between them is known as covalent bond

3. Ans. In forming oxygen molecule, two electrons are shared by each atom of oxygen.

4. Ans. forming N2 molecule, three electrons are shared by each atom of nitrogen.

5.Ans. The number of single covalent bonds in C2H2 molecule are two

6.Ans. Melting points and boiling points of ionic compounds are generally higher than those of covalent compounds.

 

Short Answer Type Questions

 

21.
(a) What is a covalent bond ? What type of bond exists in (i) CCl4, and (ii) CaCl2 ?
Ans. Sharing of electron between the atoms and form chemical bond is called covalent bond.

1) CCl4 – in CCl4 covalent bond present.
2) Cacl2 – in CaCl2 ionic bond present.

 

(c) What is an ionic bond ? What type of bond is present in oxygen molecule ?

Ans. The atom contain positive charge interact with atom contain negative charge and form bond, The forming bond is called ionic bond. In oxygen molecule

22.

(a) What is an ion ? Explain with examples.

Ans. Ion is loss or gain of electron and they possess positive or negative charge.
Examples – Sodium Na+ , Magnesium Mg2+, oxygen O2-

 

(b) What is the nature of charge on (i) a cation, and (ii) anion

Ans: Nature of charge on cation is positive and nature of charge on anion is negative.

 

(c) Name the cation and anion present in MgCl2. Also write their symbols.

Ans- The cation present in MgCl2 Mg+ and anion present Cl –

 

23.
(a) What type of chemical bond is present in chlorine molecule ? Explain your answer.

Ans. Covalent type chemical bond present in chlorine molecule because chlorine atom share electron with another atom and form covalent.

 

(b) Explain the formation of a chlorine molecule on the basis of electronic theory of valancy.
Ans. atomic number chlorine is 17 and it’s electronic configuration is 2 8 7 and chlorine need one electron for complete Octet therefore Each chlorine atom share one electron to form chlorine molecule.

 

24) 

(a) Giving one example each, state what are

(i) ionic compounds,

Ans. Positivity charge atom transfer of one electron to negatively charge atom and forming ionic bond. Ionic compound also form ionic bond. For example sodium chloride.

(ii) covalent compounds.

Ans atom share of one electron to another atom and forming bond due to strong force is called covalent bond and covalent compound form covalent bond. For example ammonia.

 

(b) Compare the properties of ionic compounds and covalent compounds.

Ans.

Ionic compound

                Covalent compound

Ionic compound contain ionic bond Covalent compound contain covalent bond
Ionic compound have high melting point and boiling point Covalent compound have low melting point and boiling point.
Ionic compound transfer of electron Covalent compound share of electron
Ionic compound form strong bond Covalent compound form weak bond
Ionic compound soluble in water. Covalent compound insoluble in water

 

25) Explain why :

 

(a) covalent compounds have generally low melting points.

Ans. covalent compounds have generally low melting points because covalent compound form weak bond due to this less energy to required bond breaking.

 

(b) ionic compounds have generally high melting points.

Ans. ionic compounds have generally high melting points because ionic compound from strong bond due to this more energy to required bond breaking.

 

26.

 (a) Give two general properties of ionic compounds and two those of covalent compounds.

Ans.

                Ionic Compound

              Covalent compound

Ionic compound contain metal – metal and  metal -non metal Covalent compound only contain non metal
Ionic compound have solid at room temperature. Covalent compound have liquid and gas form at room temperature.

 

(b) State one test by which sodium chloride can be distinguished from sugar.

Ans. Sodium particle are cubic, they have more dense than sugar hence sodium chloride easily dissolve in water and produce ion and conduct electricity but sugar dissolve in water not conduct electricity.

 

27.

(a) Explain why, ionic compounds conduct electricity in solution whereas covalent compounds do not conduct electricity.

Ans. Magnesium chloride is ionic compound and easily dissolve in water and produce ion and conduct electricity. Carbon tetrachloride is form covalent bond  and insoluble in water and not conduct electricity

 

(b). Which of the following will conduct electricity and which not ? MgCl2, CCl4, NaCl, CS2, Na2S Give reasons for your choice.

Ans. The compound contain electricity because they ionic in nature Mgcl2 NaCl  Na2S.

The compound not contain electricity because they are covalent in nature CCl4 and CS2.

 

28) 

(a) name one ionic compound containing chlorine and one covalent compound containing chlorine.

Ans. Sodium Chloride (Nacl) ionic compound containing chlorine and  carbon tetrachloride (CCl4) covalent compound containing chlorine.

(b) How will you find out which of the water soluble compound A or B is ionic ?

Ans. Water soluble compound A Or B is find out when both A Or B compound dissolve in water those molecule conduct electricity is ionic compound.

 

29) Explain why, a solution of cane sugar does not conduct electricity but a solution of common salt is a good conductor of electricity.

Ans. Cane sugar dissolve in water but is covalent in nature and not conduct electricity but common salt easily dissolve in water and conduct electricity because they are ionic nature.

 

30) Give the formulae of the compounds that would be formed by the combination of the following pairs of elements :

(a) Mg and N2

Ans:  3Mg + N2 → Mg3N2 (magnesium nitride)

 

(b) Li and O2

Ans: Li  +  O2→ Li2O (Lithium oxide)

 

(C) Al and Cl2

Al   +  Cl2  → AlCl3 ( Aluminium chloride)

 

(d) K and H

→ k  + H →  KH (potassium hydride)

 

31.

(a) What are noble gases ? What is the characteristic of the electronic configuration of noble gases ?

Ans: In periodic table 18 groups of elements are called noble gases. The Nobel gases is also called inert gases and they are not react with other atoms or elements. The characteristics of electronic configuration of Nobel gases are 8 electron in there outermost shell and their octet is complete filled except helium.

 

(b) What is the cause of chemical bonding (or chemical combination) of atoms of elements ?

Ans: cause of chemical bonding of atom of elements is due to transfer, sharing of electron and strong force of interaction are present due to forming chemical bond.

 

32.

 (i) Write electron-dot structures for magnesium and oxygen.

Ans:

 

(ii) Show the formation of MgO by the transfer of electrons?

Ans: 

 

(iii) What are the ions present in this compound ?

Ans:  In Magnesium oxide compound magnesium ion that is Mg2+ and Oxide ion O2-

 

33) 

i) Draw the electron-dot structure of a hydrogen chloride molecule :

Ans:

(ii) Which inert gas does the H atom in HCl resemble in electron arrangement ?

Ans: Helium inert gas does the H atom in HCl resemble in electronic arrangement.

 

(iii) Which inert gas does the Cl atom in HCl resemble in electron arrangement ?

Ans:Argon inert gas does the Cl atom in HCl resemble in electronic configuration.

 

34) What type of bonding would you expect between the following pairs of elements ?

 

(i) Calcium and Oxygen

Ans: when calcium react with oxygen calcium oxide form and ionic bond present calcium and oxygen.

 

(ii) Carbon and Chlorine

Ans: Carbon react  with Chlorine to form carbon tetra chloride and covalent bonding are present

 

 (iii) Hydrogen and Chlorine

Ans: hydrogen react with chlorine hydrogen chloride form and in which polar covalent bond present.

 

35) Describe how sodium and chlorine atoms are changed into ions when they react with each other to form sodium chloride, NaCl. What is the name given to this type of bonding ? (At. No of sodium = 11 ; At. No. of chlorine = 17)

Ans: 7 Valence electron are present in chlorine but chlorine need one electron to complete their octet sodium give one electron to chlorine and forming sodium chloride. In which ionic bonding present.

 

36) What is the difference between a cation and an anion ? How are they formed ? Give the names and symbols of one cation and one anion.

Ans:

 

37) Using electron-dot diagrams which show only the outermost shell electrons, show how a molecule of nitrogen, N2, is formed from two nitrogen atoms. What name is given to this type of bonding ? (Atomic number of nitrogen is 7)

Ans:

Nitrogen containfive valance electron in outermost shell. Nitrogen need more 3 electron complete their octet. Each nitrogen share 3 electron and complete their octet and forming bond. The covalent bonding present in it’s.

 

38) Draw the electron-dot structures of the following compounds and state the type of bonding in each case :

 (i) CO2 (ii) MgO (iii) H2O (iv) HCl (v) MgCl2

Ans:

CO2 – the covalent bonding present

MgO – ionic bond present in MgO

 

H2O –Covalent bond present in H2O

Mgcl2 – ionic bond present in Mgcl2

 

39) Using electron-dot diagrams which show only the outermost shell electrons, show how a molecule of oxygen, O2, is formed from two oxygen atoms. What name is given to this type of bonding ? (At. No. of oxygen = 8)

Ans: The atomic number of Oxygen is 8. The electronic configuration of oxygen is 2, 6. And their valence shell 6 electrons are present.

Oxygen molecule share 2 electron to other oxygen molecule and form chemical bond. This chemical bond is covalent bond.

 

40) Draw the electron-dot structures of the following compounds and state the type of bonding in each case :

(i) KCl (ii) NH3 (iii) CaO (iv) N2 (v) CaCl2

 

i) KCl – ionic bonding present

 

ii) NH3 –Covalent bonding present

 

iii) CaO – ionic bonding present

 

Iv)  Cacl2 –  ionic bonding present 

 

41) Explain why, a salt which does not conduct electricity in the solid state becomes a good conductor in molten state.

Ans : In solid state ion in which strong bonding interaction due to this they are not freely move in solid state and therefore not conduct electricity but conduct electricity in molten state.

 

Long Answer Type Questions

 

42.

(a) Write down the electronic configuration of :

 (i) sodium atom

Ans: the electronic configuration of sodium atom is [Ne] 3S1 and electron in per shell 2,8,1

 

(ii) chlorine atom

Ans: the electronic configuration of chlorine atom is [Ne] 3S2 3P and electron in pr shell 2,8,7

 

(b) How many electrons are there in the outermost shell of

 (i) a sodium atom

Ans:  one electron is present in sodium atom outermost shell.

 

 (ii) a chlorine atom

Ans: seven electrons are present in chlorine atom outermost shell

 

(c) Show the formation of NaCl from sodium and chlorine atoms by the transfer of electron(s).

Ans:   In sodium chloride sodium contain one electron in outermost shell and chlorine contain seven. When sodium transfer one electron to chlorine, get eight electron to chlorine octet Will be complete and molecule get stabilize with forming ionic bonding.

 

(d) Why has sodium chloride a high melting point ?

Ans: sodium chloride( NaCl ) is ionic compound and form strong ionic bond. Due to strong bonding bond are not break easily more energy required hence sodium chloride has high melting point.

 

(e) Name the anode and the cathode used in the electrolytic refining of impure copper metal.

Ans: Impure Copper anode (positive electrode) used in the electrolytic refining of impure copper metal

Pure copper cathode (negative electrode) in the electrolytic refining of copper metal.

 

43.

 (a) Write the electron arrangement in

 (i) a magnesium atom

Ans: electron arrangement in Magnesium – 2 8 2

 

(ii) an oxygen atom.

Ans: electron arrangement in oxygen –2,6

 

(b) How many electrons are there in the valence shell of

 (i) a magnesium atom, and

Ans: 2

 

(ii) an oxygen atom ?

Ans: 6

 

(c) Show on a diagram the transfer of electrons between the atoms in the formation of MgO.

Ans: Magnesium transfer two electron to oxygen and forming MgO

 

(d) Name the solvent in which ionic compounds are generally soluble.

Ans: Water is solvent and in which ionic compound generally soluble.

 

(e) Why are aqueous solutions of ionic compounds able to conduct electricity ?

Ans: Aqueous solution of ionic compounds able to conduct electricity because ionic compound are completely dissolve and their completely free ion generate and they are easily conduct electricity.

 

 44.

 (a) What is the electronic configuration of

(i) a sodium atom, and

Ans: Electronic configuration of sodium atom is 2 8 1 and 1S2 2S2 2P6 3s1

 

(ii) an oxygen atom

Ans: electronic configuration of oxygen atom is 2 6  and 1S2 2S2 2P6

 

(b) What is the number of outermost electrons in

 (i) a sodium atom, and

Ans: Outermost electron in sodium atom is 1

 

 (ii) an oxygen atom ?

Ans: outermost electron in oxygen atom is 6

 

(c) Show the formation of Na2O by the transfer of electrons between the combining atoms.

Ans:

Sodium atom transfer electron to oxygen and Form Na2O compound. It is ionic compound.

(d) Why are ionic compounds usually hard ?

Ans: Ionic compound usually hard because in ionic compound positively charge ion attract with negatively charge ionwith strongly force of interaction form ionic compound in crystal form.

 

(e) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state ?

Ans: Ionic compound in solid state they do not conduct electricity because in solid state there ion are strongly held with each other and not conduct electricity. But in molten state ionic compound ions free form and easily conduct electricity.

 

45.

 (a) Write down the electron arrangement in

 (i) a magnesium atom, and

Ans: electron arrangements of magnesium 2 8 2 or 1S2 2S2 2P6 3S2

 (ii) a chlorine atom.

Ans: electron arrangements of chlorine 2 8 7 or 1S2 2S2 2P6 3S2 3P5

 

(b) How many electrons are there in the valence shell of

 (i) a magnesium atom, and

Ans: in magnesium valence shell 2 electron present.

(ii) a chlorine atom

Ans: in chlorine valence shell 7 electron present.

 

d) Show the formation of magnesium chloride from magnesium and chlorine by the transfer of electrons.

Ans:-

Magnesium atom transfer electron to both chlorine atom and forming ionic compound that is magnesium dichloride

 

e) State whether magnesium chloride will conduct electricity or not. Give reason for your answer.

Ans:  Magnesium chloride will conduct electricity because magnesium chloride is ionic compound it dissolve in aqueous solution and their ion completely free. The free ion able to conduct electricity.

 

f) Why are covalent compounds generally poor conductors of electricity ?

Ans:  Covalent compound generally poor conductor of electricity because covalent compound strongly hold with each other due to this they not dissolve in aqueous solution and not form free ion to conduct electricity.

 

Part 3 Solutions

 

Very Short Answer Type Questions

 

1.) A zinc ore gave CO2 on treatment with a dilute acid. Identify the ore and write its chemical formula.

Ans:-  ZnCO3(s) + HCl (dil) → Zncl2+ CO2 + H2O

Zinc carbonate + hydrochloric acid → zinc chloride + carbon dioxide + water

Ore is zinc carbonate
Chemical formula of ore – ZnCO3

 

2.) What chemical process is used for obtaining a metal from its oxide ?

Ans: chemical process used for obtaining metal from its oxide is reduction

 

3.State two ways to prevent the rusting of iron.

Ans: The two ways to prevent the rusting of iron are
1.) Galvanize
2.) Painting

 

4. What is meant by galvanization ? Why is it done ?

Ans: Galvanization is coating method zinc coat over iron or steel. Galvanization process is done by rusting of iron.

 

5.Name the metal which is used for galvanising iron.

Ans: zinc metal used for galvanizing iron because zinc not react with air and prevent corrosion of iron or steel.

 

6. Explain why, iron sheets are coated with zinc.

Ans: Zinc protect iron sheet for corrosion therefore iron sheets coated with zinc.

 

7. Why do we apply paint on iron articles ?

Ans: we apply paint on iron articles because paint protect iron sheet from rusting.

 

8. Give reason for the following : Carbonate and sulphide ores are usually converted into oxides during the process of extraction of metals.

Ans: The extraction of metal easy from metal oxide hence carbonate and sulphide ore are usually converted into oxide during the process of extraction of metals.

 

9. Name a reducing agent that may be used to obtain manganese from manganese dioxide.

Ans: Aluminium powder is reducing agent that used to obtain manganese from manganese dioxide.

 

10. Name an alloy of lead and tin.

Ans: Solder alloy of lead and tin.

 

11. Give the composition of an alloy called solder. State its one property and one use.

Ans: ratio of tin and lead 50:50 composition of an Solder alloy.

Property of solder – solder have low melting point.

Use of solder –solder use for welding electric wire.

 

12. What is an amalgam ?

Ans: amalgam is an alloy and combination of mercury and other metal.

13. How many carats is pure gold ? Why is pure gold not suitable for making ornaments ?

Ans: 24 carats is pure gold. Pure gold is very soft for making ornaments and hence copper mix with gold making ornaments.

 

14. Name one method for the refining of metals.

Ans: Electrolysis method use for the refining of metals.

 

15. State two conditions for the rusting of iron.

Ans: Two conditions for the rusting of iron

1. In presence of water
2. In presence of air

 

16. In one method of rust prevention, the iron is not coated with anything. Which is this method ?

Ans: Galvanizing is one of the method of rust prevention in which iron not coating with anything.

 

17. Name two alloys of iron. What elements are present in these alloys ?
Ans: Alloy of iron is steel and stainless steel. The elements present in steel is iron and in stainless steel iron, nickel, chromium elements present.

 

18. Give reason for the following : Silver, gold and platinum are used to make jewellery.

Ans: Silver, Gold and Platinum are soft metal easily give shape therefore used for making jewellery.

 

19. Which metal becomes black in the presence of hydrogen sulphide gas in air ?

Ans: silver metal becomes black in the presence of hydrogen sulphide gas in air.

 

20. Name the gas in air which tarnishes silver articles slowly.

Ans: In air hydrogen sulphide gas tarnishes silver article slowly, hydrogen sulphide gas react with silver Black colour thin layer present on silver metal.

 

21. Silver metal does not combine easily with oxygen but silver jewellery tarnishes after some time. How?

Ans: Silver metal does not combine easily with oxygen but silver jewellery tarnishes after some times because silver metal react with hydrogen sulphide in air therefore silver jewellery tarnishes.

 

22. Write the composition of the alloy called bronze. Give two uses of bronze.

Ans. Composition of the 90% copper and 10% zinc alloy called bronze.

The two uses of bronze are making statue and coins.

 

23. Why does a new aluminium vessel lose shine so soon after use ?

Ans: new aluminium vessel lose shine so soon after use because it react with oxygen in air and form aluminium oxide.

 

24. Why do gold ornaments look new even after several years of use ?

Ans: gold ornaments look new even after several years of use because on gold met no effect of oxygen air and water.

 

25. Name two metals which are highly resistant to corrosion.

Ans. Two metals which are highly resistant to corrosion are gold and platinum.

 

26. Which property of ‘solder’ alloy makes it suitable for welding electrical wires ?

Ans. Solder alloy melting point is very low and suitable for welding electric wires.

 

27. Explain why, carbon cannot reduce oxides of sodium or magnesium.

Ans:

 

28. Why are the metals like Na, K, Ca and Mg never found in their free state in nature ?

Ans: the metals like Na, K, Ca and Mg never found in their free state in nature because Na, K, Ca and Mg metals are highly reactive and it react with non metal to complete their octet.

 

29. Name one metal each which is extracted by :-

 

(a) reduction with carbon.

Ans: zinc metal extracted from reduction with carbon

 

(b) electrolytic reduction.

Ans: potassium metal extract with electrolytic reduction

 

(c) reduction with aluminium

Ans: Manganese metal extract with reduction with aluminium

 

(d) reduction with heat alone.

Ans: Mercury metal extract reduction with heat alone.

 

30. Fill in the following blanks with suitable words :

 

(a)  Ans: The corrosion of iron is called rusting

 

(b) Ans: Water and Oxygen are necessary for the rusting of iron

 

(c) Ans: The process of depositing a thin layer of zinc on iron articles is called galvanization

 

(d) Ans: Tiffin boxes are electroplated with steel but car bumpers are electroplated with zinc to protect them from rusting.

 

(e) The corrosion of copper produces a ……………. coating of basic copper carbonate on its surface.
Ans:

 

(f)  Ans: Brass is an alloy of copper and zinc

 

(g) Ans: Bronze is an alloy of copper and zinc

 

(h) Ans: The non-metal present in steel is Carbon

 

(i) Ans: The alloy in which one of the metals is mercury is called an amalgam

 

(j) Ans: The electrical conductivity and melting point of an alloy is less than that of pure metals.

 

(k) Ans: The rocky material found with ores is called gangue

 

Short Answer Type Questions

 

31. How is manganese extracted from manganese dioxide, MnO2 ? Explain with the help of an equation.

Ans: When manganese oxide react with aluminium under heating condition the manganese form.

3MnO2(s) + 4Al(s) → 3Mn + 2Al2O3

Here aluminium act as reducing agent.

32. What is a thermite reaction ? Explain with the help of an equation. State one use of this reaction.

Ans: The reaction between metal and metal oxide under exothermic condition is called thermite reaction.

For example. Iron oxide react with aluminium under exothermic condition iron metal produce.

Fe2O3+ 2Al → 2Fe + Al2O3

Use of thermite reaction :

  • Thermite reaction is use for metal refining.

 

33. Which one of the methods given in column I is applied for the extraction of each of the metals given in column II :

           Column l                 Column ll
Electrolytic reduction Aluminium
Reduction with carbon Zinc
Reduction with aluminium Sodium
Iron
Manganese
Chromium

 

Ans: Electrolytic reduction – Aluminium and Sodium

Reduction with Carbon –zinc ,iron ,tin

Reduction with aluminium- Manganese and chromium

 

34.

(a) Give reason why copper is used to make hot water tanks but steel (an alloy of iron) is not.

Ans : Copper is used to make water tank but steel (an alloy of iron) is not because copper not react with water not affected on tank but steel means alloy of iron react with water to corrode tank.

(b) Explain why, the surface of some metals acquires a dull appearance when exposed to air for a long time.

Ans: when metal contact with air for a long time metal react with oxygen and other gases in air , the thin layer of oxide or other gases metal surface therefore metal acquires a dull appearance.

 

35.

(a) Why does aluminium not corrode right through ?

Ans: Aluminium is highly react with oxygen and aluminium oxide form. On aluminium surface oxygen layer are present. Oxide layer is very hard hence no any one effect on it. Aluminium prevent from corrosion . Thus aluminium article not react with oxygen and water because strong oxide layer on it surface.

 

(b) What is meant by ‘anodising’ ? Why is it done ?

Ans: Metal surface coating with oxide layer this process is called anodising. Aluminium Oxide is used for coating because it prevent to corrosion.

 

36.

(a) Why is an iron grill painted frequently ?

Ans: Iron grill paint frequently because iron easily react with water and oxygen. It is fast corrode.

 

(b) Explain why, though aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.

Ans: Aluminium is more reactive than iron therefore aluminium easily react with oxygen in air and form aluminium oxide. Aluminium oxide layer on it surface and those layer strong not affect on it water or oxygen. And hence aluminium prevent from corrosion.

 

37.

(a) Name the method by which aluminium metal is extracted.

Ans: Electrolytic reduction method is use aluminium metal extracted.

(b) Give the name and chemical formula of one ore of copper

Ans: Copper pyrite CuFeS2.

 

(C) How is zinc extracted from its carbonate ore (calamine) ? Explain with equations.

Ans: The carbonate ore is also known as calamine. When calamine react with zinc oxide under heating condition to form zinc metal.

ZnO + C → Zn + CO

 

38.

(a) Name two Name two metals which occur in nature in free state as well as in combined state..

Ans: Copper and Silver metals which occur in nature in free state as well as in combined state.

 

(b) Name one ore of manganese. Which compound of manganese is present in this ore ? Also write its chemical formula.

Ans: Pyrolusite is ore of manganese. Manganese dioxide compound of manganese is present in this ore. The chemical formula is MnO2.

 

(c) A zinc ore on heating in air forms sulphur dioxide. Describe briefly any two stages involved in the conversion of this concentrated ore into zinc metal.

Ans: when zinc ore on heating in air sulphur dioxide form in two stage are involved that is roasting and reduction of metal.
I) Roasting –when zinc ore is heated with air it form zinc oxide and sulphur dioxide.
II) Reduction of metal – when zinc oxide reduced with carbon zinc metal obtain.

 

39. How does the method used for extracting a metal from its ore depend on the metal’s position in the reactivity series ? Explain with examples.

Ans: According to reactivity series top to bottom reactivity decreases and metal extraction from its ore depend on the metals position in reactivity series.

In reactivity series, reactive metal classified into three class –

  • Highly reactive metal
  • Moderately reactive metal
  • Least reactive metal

 

[A] Highly reactive metals – the highly reactive metals place at top in reactivity series and they are extract by electrolytic reduction method by their molten chloride and oxides because they are not reduce with other reducing agent.

[B] Magnesium metal extract by reduction of aluminium because magnesium metal more reactive than zinc.

[C] Moderately reactive metals – zinc, iron, lead are moderately reactive metals they are extract by reduction of their metal oxide with carbon because is more reactive than these metals.

[D] least reactive metals –copper and zinc are less react metals they are extract by reduction by heating.

[E] silver and gold are very least reactive metals and they found in free state in nature.

40. Explain giving one example, how highly reactive metals (which are high up in the reactivity series) are extracted.

Ans: The highly reactive metals like Potassium, Sodium, Calcium Magnesium, Aluminium.
For example – Sodium is highly reactive metal which extract by electrolytic reduction method with theirs molten chloride Or oxides.

2Na (l) + electrolysis → 2Na(s) + Cl2(g)

41. Describe with one example, how moderately reactive metals (which are in the middle of reactivity series) are extracted.

Ans: zinc, iron, lead are moderately reactive metals.

For example – Zinc metal extract by reduction of their metal oxide with carbon because is more reactive than these metals.

ZnO(s) + CO(g) → Zn(s) + CO2 (g)

 

42. How are the less reactive metals (which are quite low in the reactivity series) extracted ? Explain with the help of an example.

Ans: copper and mercury are less react metals.

For example –mercury metal they are extract by reduction by heating.

2HgO +(heating) → Hg + O2

 

43. What is meant by refining of a metal ? Name the most widely used method for the refining of impure metals obtained by various reduction processes. Describe this method with the help of a labelled diagram by taking the example of any metal.

Ans: Refining is the process of purifying impure metal.
The electrolytic refining method is use for refining of impure metals obtained by various reduction process.

The electrolytic refining method –

Electrolytic refining is a method is used for the extraction and purification of metals that are obtain by reduction process. In electrolytic refining process impure metal is used as an anode and pure metal is used as cathode. Acidified copper sulphate solution used in this process. When electric current is passed, pure metal gets deposited at the cathode and the impure metal gets dissolved from the anode. Impurities from the metal present at below the anode and is know as anode mud. In electrolytic refining process impure metal such as copper, gold, silver, platinum, Arsenic etc metals are purifying.

Example of electrolytic refining process:

  • Copper metal is example of electrolytic refining.

In above figure the electrolytic tank contain with electrolyte as acidified copper sulphate solution. A thin strip of pure copper metal is used as cathode. A thick Strip of impure copper metal is used as anode.

 

At Cathode :
Cu2+ + 2e– → Cu

At anode :
Cu — 2e– → Cu2+

 

44. (a) Define the terms

(i) mineral

Ans: The naturally occurring substances in the earth crust which are obtained by mining are know as minerals.

 

(ii) ore

Ans: The substance which obtained from mineral easily and profitably is called ore.

 

(iii) gangue

Ans: The impurities present in the ore such as sand rock etc is known as gangue.

 

(b) What is meant by the ‘concentration of ore’ ?

Ans: The concentration of ore is the process in which to remove the impurities from the ore. This process is also called dressing or benefaction.

 

(c) Name one ore of copper (other than cuprite). Which compound of copper is present in this ore ? Also, write its chemical formula.

Ans: Copper glance is one of the ore of copper.
Copper (l) sulphide compound of copper is present in copper glance ore.
The chemical formula of copper glance ore is Cu2S.

 

45.Explain how, a reduction reaction of aluminium can be used for welding cracked machine parts of iron. Write a chemical equation for the reaction involved.

Ans: When iron oxide (lll) react with aluminium under heating conditionwith magnesium burning. Aluminium reduce iron oxide to produce Iron and aluminium oxide with heating.

 

46.

(a) What is corrosion ?

Ans: Corrosion is the deterioration of a metal as a result of chemical reaction between it and the surrounding environment.

 

(b) Name any two metals which do not corrode easily.

Ans: Gold and platinum both metals which do not corrode easily.

 

(c) What is the corrosion of iron known as ?

Ans: The corrosion of iron know as rusting.

 

(d) Explain why, aluminium is a highly reactive metal, still it is used to make utensils for cooking.

Ans: Aluminium is a highly reactive metal still it is used to make utensils for cooking because aluminium metal react with oxygen in air and form aluminium oxide and aluminium oxide layer present on it’s surface. This metal prevent corrosion.

 

47. What is meant by ‘rusting of iron’ ? With the help of labelled diagrams, describe an activity to find out the conditions under which iron rusts.

Ans: Rusting of iron is when iron contact with moist air for a long time , brown color coating on iron surface this process is called rusting of iron.

 

Activity to find out the conditions under which iron rusts is following :

  • 1. Take three test tube A, B, C.
  • 2. In test tube A add water and nails in it and cork it.
  • 3. In test tube B put nails and add boil water and 1ml oil and cork it.
  • 4. In test tube C add anhydrous calcium chloride and add nails and cork it.
  • 5. Leave all test tube for one day and observe it.

Observation :

  • 1. In test tube A iron nails get rusted because in presence of water and air iron nails rust.
  • 2. In test tube B iron nails not rusted because irons presence in water but absence of air.
  • 3. In test tube C iron nails not rusted because here water and air absence.
    Conclusion : iron nails get rusted in presence of water and air .

 

48.

(a) What is an alloy ? How is an alloy made ?

Ans: Alloy is mixture of two or more metals and non metal also. An alloy is made by heating the components in fixed proportion and then uniformly mixed with molten state and cooling.

 

(b) What elements are present in steel ? How are the properties of steel different from those of pure iron ?
Ans: In steel iron and carbon elements present.
the properties of steel different from those of pure iron :

Steel is alloy of iron is hard and strong. Steel is less rust than pure iron.

 

(c) Give the constituents and one use of brass.

Ans: Brass contains copper and zinc.

Brass use for cooking utensils.

 

49.

(a) Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.

Ans: Aluminium and Zinc two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.

 

(b) Name five methods of preventing rusting of iron.

Ans: five methods of preventing rusting of iron are the following :

  • 1.Galvanize
  • 2.Paint the iron
  • 3.Blueing
  • 4.apply oil
  • 5.Powder coating

 

(c) What are the constituents of stainless steel ? What are the special properties of stainless steel ?

Ans: the constituents of stainless steel are chromium and nickel. The special properties of stainless steel is stainless steel does not rust and is strong and tough.

 

50.

(a) Name an alloy of copper. State its chemical composition and any one use.

Ans: Bronze is an alloy of copper.The chemical composition of bronze is 90% copper and 10% tin. Bronze is tough and hard it is used for prevents corrosion.

 

(b) Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as ?
Ans: when a copper object remains in damp air for a considerable time, a green coating is formed on its surface because when copper Object react with Carbon dioxide and moisture in air to form green layer of copper carbonate (CuCO3.Cu(OH) 2) on surface of copper object. This process is know as corrosion.

 

51.
(a) How does the painting of an iron object prevent its rusting ?

Ans: The painting of an iron object prevent its rusting because it is simple method to prevent rusting of iron object is painting the surface of iron objects. Rusting process take place in presence of water and air. When paint apply on the surface of an iron object it prevents the contact of air and moisture with iron surface and prevent from rusting of iron.

 

(b) How does the electrical conductivity of copper alloys, brass and bronze, differ from that of pure copper ?

Ans: Pure copper is good conductor of heat and electricity as compare to the copper alloy, brass and bronze are poor conductor of electricity.

(c) What is meant by 22 carat gold ? Name the metals which are usually alloyed with gold to make it harder.

Ans: 22 carat gold means 22 parts of pure gold and 2 parts of other metal that make the texture of gold harder. Copper and silver metals which are usually alloyed with gold to make it harder.

 

52. Explain giving equation, what happens when :

(a) ZnCO3 is heated in the absence of air ?

Ans: when zinc oxide heated in absence of air to form zinc zinc oxide and carbon dioxide.

 

(b) a mixture of Cu2O and Cu2S is heated ?

Ans: When mixture of copper oxide and copper sulphide heated to form copper.

 

53) 

(a) For the reduction of a metal oxide, suggest a reducing agent other than carbon.

Ans: Aluminium used to reducing agent other than carbon for the reduction of a metal.

 

(b) Explain why, an aqueous solution of sodium chloride is not used for the electrolytic extraction of sodium metal.

Ans: aqueous solution of sodium chloride is not used for the electrolytic extraction of sodium metal because on electrolyzing an aqueous solution of sodium chloride , sodium metal Is produced at the Cathode, which react with water present in the aqueous solution of to sodium hydroxide.

 

54) How are metals refined by the electrolytic process ? Describe the electrolytic refining of copper with the help of a neat labelled diagram.

Ans: Impure Metals refined by the electrolytic process. Metals like zinc , copper, tin, lead, silver, gold are refined by electrolytic process.

Electrolytic refining of Copper:

An electrolytic refining tank consist of an anode,cathode and electrolyte. Thick rod of an impure metal is made the anode and attached the positive end. Thin rod of pure metal is made the cathode and attached to negative end. When electricity is passed through the cell, impure metal from the anode get deposited there as pure metal. While the solution impurities dissolve in the electrolyte, the insoluble ones deposit under the anode as anode mud.

Following reactions take place at cathode and anode when electricity passed through the electrolytic cell :

I) impure copper atoms from the anode lose two electrons form copper ion and enter copper sulphate electrolyte.

II) copper ions from the copper sulphate electrolyte move to the cathode by gain two electrons from cathode.

 

55) 

(a) Name the chemical compound which is electrolysed in molten state to obtain aluminium metal. Which gas is evolved during this process ?

Ans: Aluminium compound which is electrolysed in molten state to obtain aluminium metal and oxygen gas is evolved during this process.

 

(b) Name the chemical compound which is electrolysed in molten state to obtain sodium metal. Which gas is produced in this process ?

Ans: Sodium chloride which electrolysed in molten state to obtain sodium metal and chlorine gas is produced in this process.

 

(c) Name the gas produced when calamine ore is calcined.

Ans: Carbon dioxide gas produced when calamine ore is calcined.

 

(d) Name the gas evolved when cinnabar ore is roasted.

Ans: Sulphur dioxide gas evolved when cinnabar ore is roasted.

 

56) (a) Name two metals which are found in nature mainly in the free state (as metallic elements).

Ans: Gold and silver metals which are found in nature mainly in the free state.

 

(b) Name two metals which are always found in combined state.

Ans: Sodium and magnesium are always found in combined state.

 

(c) What iron compound is present in haematite ore ? Also write its chemical formula.

Ans: Iron (III) oxide compound present in haematite ore. Chemical formula is Fe2O3.

 

Long Answer Type Questions

 

57.

(a) What is the difference between a mineral and an ore ?

Minerals
Ores
1.Minerals are naturally occurring compound from earth crust. 1.ores are those minerals from which metal can be extracted profitably.
2. All minerals are not ores. 2.All ores are minerals
3.bauxite are minerals of aluminium 3.Aluminium is ore of bauxite.

(b) Which metal is extracted from cinnabar ore ?

Ans: Mercury metal is extracted from cinnabar ore.

 

(c) Name one ore of sodium. Name the sodium compound present in this ore and write its chemical formula.

Ans: Ore of sodium is rock salt and in rock salt sodium chloride present. The chemical formula  of the ore is NaCl.

 

(d) How is sodium metal extracted ? Explain with the help of equation of the reaction involved.

Ans:  Sodium metal is extracted from electrolytic reduction of molten sodium chloride. Sodium metal extract when electric current passed through molten chloride.

 

(e) Name three other metals which are extracted in a manner similar to sodium.

Ans: Potassium, Calcium and aluminium metals which are extract in a manner similar to sodium because they are highly reactive and reduce easily.

 

58.

(a) Name the metal which is extracted from haematite ore.

Ans: iron metal which is extracted from haematite ore.

 

(b) Name one ore of aluminium. Name the aluminium compound present in this ore and write its chemical formula.

Ans: Bauxite is ore of aluminium. Name the aluminium compound present in this ore and its chemical formula is 2Al2O3.2H2O

 

(c) How is aluminium metal extracted ? Explain with the help of an equation.

Ans: Aluminium metal extracted by electrolysis method. When electric current passed through aluminium oxide and it decompose to form aluminium metal and liberate oxygen gas.

(d) Name the electrode at which aluminium metal is produced.

Ans:Cathode electrode at which aluminium metal is produced.

 

(e) Which gas is produced during the extraction of aluminium ? At which electrode is this gas produced ?

Ans: Oxygen gas is produced during the extraction of aluminium. At anode electrode is oxygen gas produced.

 

59) 

(a) Which metal is extracted from bauxite ore ?

Ans: Aluminium metal is extracted from bauxite ore.

 

(b) Give the name of one ore of iron. Which iron compound is present in this ore ? Write its chemical formula.

Ans: Hematiteis ore of iron. Iron (III) oxide present in this ore. The chemical formula is Fe2O3.

 

(c) Describe the extraction of zinc metal from its sulphide ore (zinc blende). Write equations of the reactions involved.

Ans:  Zinc sulphide is heated in presence of air it form zinc oxide and sulphur dioxide. This process is know as roasting.

Zinc oxide is heated with carbon form zinc metal. This process is know as reduction.

(d) Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.

Ans: The galvanised iron article is protected against rusting even if the zinc layer is  broken because zinc is more easily oxidised than iron. Hence zinc corrode but iron object does not corrode.

 

(e) Name a common metal which is highly resistant to corrosion.

Ans: Aluminium metal which is highly resistant to corrosion.

 

60.

(a) Name the metal which is extracted from the ore called ‘rock salt’.

Ans: The sodium metal which is extracted from the called rock salt.

 

(b) Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.

Ans: Calamine ore and zinc blend these two ores of zinc.

Calamine ore in which Zinc carbonate chemical compound present and their chemical formula is ZnCO3.

Zinc blend ore in which zinc sulphide chemical compound present and their chemical formula is ZnS.

 

(c) Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equations of the reactions involved.

Ans: Mercury (ll) sulphide ore is roasted in air then Mercury (ll) oxide is form.

When Mercury (ll) oxide is heated at 300°C  it decompose and form Mercury metal.

(d) In the electrolytic refining of a metal M, what would you take as anode, cathode and electrolyte ?

Ans: In electrolytic refining of a metal M, anode take as thick block impure metal M. and Cathode take as thin Strip of metals M. Electrolytes take as water soluble salt.

 

(e) Name any five metals which are purified by electrolytic refining method.

Ans: Copper, Zinc, Golden, Silver, Nickel metals which arepurified by electrolytic refining method.

 

61) 

(a) Which metal is extracted from calamine ore ?

Ans: zinc metal is extract from calamine ore.

 

(b) Name one ore of mercury. Which mercury compound is present in this ore ? Write its chemical formula.

Ans: Calamine is an ore of Mercury. Mercury (ll) sulphide compound present in this air. The chemical formula of this ore is HgS.

 

(c) How is copper extracted from its sulphide ore (copper glance), Cu2S ? Explain with equations of the reactions involved.

Ans: when copper sulphide ore is roasted in air then copper  get convert to copper oxide.

When more amount of copper sulphide has been converted to copper oxide supply of air For roasting stop. In absence of copper formed above react copper sulphide to form copper metal sulphur dioxide.

(d) What is an alloy ? Give two examples of alloys.

Ans: Alloy is an homogenous mixture of two or more metal. Steel and brass are example of alloys.

 

(e) How are the properties of an alloy different from those of the constitutent elements ?

Ans:

  • Alloy are hard than those constituents metal.
  • Alloy are low melting point other than those constituent metal.
  • Alloy of poor electrical conductivity than constituents metal.
  • Alloy are more resistant to corrosion.
  • Alloy are harder than constituents metal.

 

Here is your solution of Lakhmir Singh Class 10 Chemistry 3rd Chapter Metals and Non- metals Solution

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Updated: May 28, 2022 — 4:23 pm

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