Case Study Questions Class 10 Science Chapter 3 Metals and Nonmetals
CBSE Class 10 Case Study Questions Science Metals and Nonmetals. Important Case Study Questions for Class 10 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Metals and Nonmetals.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Based Questions Class 10 Science Chemistry Chapter 3
CASE STUDY :1
Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand, etc., called gangue. The impurities must be removed from the ore prior to the extraction of the metal. The processes Several steps are involved in the extraction of pure metal from ores.Metals and Non-metalsused for removing the gangue from the ore are based on the differences between the physical or chemical properties of the gangue and the ore. Different separation techniques are accordingly employed.
i) What are the process for the extraction of metals of low reactivity series?
Ans: Oxides of these metals are reduced to metal by simply heating.
ii) What is meant by Roasting?
Ans: The sulphide ores are converted into oxides by heating strongly in the presence of excess air. This is called as Roasting.
iii) Give one example of extracting metals low in the activity series.
Ans: 2Cu2O + 3O2+ heat π 2Cu2O(s) + 2SO2(g)
On further heating: 2Cu2O + Cu2S + heatπ 6 Cu(s) + SO2(g)
iv) What is the another name for HgS an ore of mercury?
Ans: HgS is also called as Cinnabar.
v) In which form does metals of low activity series occur in the earth crust?
Ans: They occur in a free state. Example- Gold
CASE STUDY 2 Metals and Nonmetals
The metals in the middle of the activity series such as iron, zinc, lead, copper, etc., are moderately reactive. These are usually present as sulphides or carbonates in nature. It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides. The sulphide ores are converted into oxides by heating strongly in the presence of excess air. This process is known as roasting. The carbonate ores are changed into oxides by heating strongly in limited air. This process is known as calcination
i) What is Calcination?
Ans: The carbonates ores are changed into oxides by heating strongly in limmited air. This process is known as Calcination.
ii) Give a suitable example for the process Roasting.
Ans: 2Zn(s) + 3O2(g) + heat π 2ZnO(s) + 2SO2(g)
iii) What is the process of converting metal oxide to metal?
Ans: The metal oxides are reduced to corresponding metal by simply using suitable reducing agents such as coke(carbon).
iv) Name some other reducing agent which can be used to extract metal from metal oxide?
Ans: Aluminium, Sodium and Calcium
v) Give the complete reaction when manganese dioxide is heated with Aluminium powder.
Ans: 3MnO2(s) + 4Al(s) π 3Mn(l) + 2Al2O3(s) + heat
CASE STUDY : 3 on Metals and Nonmetals
Β Silver articles become black after some time when exposed to air. This is because it reacts with sulphur in the air to form a coating of silver sulphide.
Β Copper reacts with moist carbon dioxide in the air and slowly loses its shiny brown surface and gains a green coat. This green substance is copper carbonate.
Β Iron when exposed to moist air for a long time acquires a coating of a brown flaky substance called rust. Let us find out the conditions under which iron rusts.
i) Write a chemical reaction occur during the rusting of iron.
Ans: Fe(s) + O2(g) + H2O(l) π Fe2O3. XH2O
ii) Give three methods to prevent the corrosion of metals.
Ans: Galvanization, painting & oiling, anodizing or making alloys.
iii) What do you meant by the alloy? Give one example.
Ans: An alloy is a homogeneous mixture of two or more metals or a metal and a non- metal.
Eg: Iron is mixed with Nickel and Chromium to give stainless steel.
iv) What is meant by Galvanization?
Ans:It is a method of protecting steel and iron from rusting by coating them with a thin layer of zinc.
v) What is amalgam?
Ans: The alloy which contains mercury as one of the metals is called amalgam.
CASE STUDY : 4
Β Collect all the metal samples except sodium and potassium again. If the samples are tarnished, rub them clean with sand paper. CAUTION: Do not take sodium and potassium as they react vigorously even with cold water.
Β Put the samples separately in test tubes containing dilute hydrochloric acid.
Β Suspend thermometers in the test tubes, so that their bulbs are dipped in the acid.
Β Observe the rate of formation of bubbles carefully.
Β Which metals reacted vigorously with dilute hydrochloric acid?
Β With which metal did you record the highest temperature?
Β Arrange the metals in the decreasing order of reactivity with dilute acids.
i) Write the reactions of magnesium with Hydrochloride acid.
Ans: Mg(s) + HCl(aq) π MgCl2 + H2(g)
ii) What happens when a metal reacts with nitric acid?
Ans: When metal react with nitric acid, it form nitrogen oxides and water. HNO3 is a strong oxidising agent, so itself reduce to nitrogen oxide.
iv) What is aqua regia?
Ans: It is a freshly prepared mixture of concentrated HCl and Conc. Nitric acid in the ratio of 3:1. It is highly corrosive and fuming liquid.
iv) What happens when Aluminium react with dil. HCl?
Ans: 2Al(s) + 6HCl(aq) π 2AlCl3(aq) + 3H2(g)
V) Reaction of metal with acid is an exothermic or endothermic reaction?
Ans: It is an exothermic reaction.
CASE STUDY : 5
Metal oxides are basic in nature. But some metal oxides, such as aluminium oxide, zinc oxide, etc., show both acidic as well as basic behaviour. Such metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides.
Most metal oxides are insoluble in water but some of these dissolve in water to form alkalis
i) Write a chemical reaction of Aluminium when burnt in air?
Ans- 4Al + 3O2 π 2Al2O3
ii) Give a example of amphoteric oxide with reaction.
Ans- Al2O3 + 6HCl π 2AlCl3 + 3H2O
Al2O3 + 2NaOHπ 2NaAlO2 + H2O
iii) Why potassium and sodium is kept under the kerosene oil?
Ans: Both the elements are highly reactive metals, so they react easily with air and water and catches fire.
To prevent from fire, they are stored under the kerosene oil.
iv) Name two oxide when are soluble in water and form alkalis?
Ans: Sodium Oxide and potassium oxide.
v) Write a equation of sodium oxide with water.
Ans: Na2O(s) + H2O(l) π 2NaOH(aq)
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