Chhattisgarh State Board Class 10 Science Chapter 9 Metals and Metallurgy Exercise Multiple Choice, Fill in the Blanks, Questions and Answers here.
Chhattisgarh State Class 10 Science Chapter 9 Solution
1) Choose the correct option–
(i) Which among the following metals is most reactive–
(a) Mg (b) Al
(c) Na (d) Zn.
Ans: – (Na).
(ii) The formula of bauxite ore is–
(a) MgCO3
(b) Al2O3.2H2O
(c) Fe2O3
(d) SnO2.
Ans: – (b)
(iii) Which method among the following is used in concentration of iron pyrite–
(a) Magnetic separation (b) Gravity separation
(c) Froth floatation (d) Electrolysis.
Ans: – (c) Forth floatation.
(iv) Calcium silicate is–
a) Alloy (b) Gangue (c) Slag (d) Flux.
Ans: – (c) slag.
(v) The constituent metals in stainless steel are–
(a) Copper, zinc and tin (b) Iron, chromium and nickel
(c) Copper, iron and zinc (d) Iron, tin and aluminium.
Ans: – (b).
2) Fill in the blanks
(i) The process of removal of a less active metal from its salt solution by a more reactive metal is known as …………….displacement…. reaction.
(ii) The primary iron ore found in Chhattisgarh is …………………hematite….
(iii) Alloys are …………… heterogeneous…………. mixture of two ormore metal or metals and non-metals.
(iv) The process of heating an ore at a temperature a little below its melting point in the absence of oxygen is called ………… calcination….
3) Explain the following
(i) Ore (ii) mineral (iii) slag (iv) flux.
Ans: – (i) Ore: – From which the source of mineral isextracted is known as ore.
(ii) mineral: – Mineral are the substance from which any metal is extracted by various method removing the impurities from it.
(iii) Slage: – The impurities which are left after the extracting the metal from a mineral is known as slage which present in oxide form.
(iv) flux: – The flux is the flow of energy in a surface form one direction to the other.
4) Write the balance chemical equations for the given reactions:
(i) Reaction of aluminium metal with steam.
(ii) Reaction of zinc oxide with sodium hydroxide.
(iii) Reaction when calcium carbonate is heated.
(iv) Reaction of oxygen with sodium.
Ans: –
(i) 2Al + 3H2O = Al2O3 +3H2.
(ii) ZnO + 2NaOH = ZnNa2O3 + H2.
(iii) CaCO3 –> CaO + CO2.
(iv) 4Na + O2 –> 2Na2O.
5) Explain the process of reduction of metal from a metal oxide.
Ans: – The metal is present like oxides ore in the ore. So, these oxides are removed from the metal by the process of reduction. This reduction process performs in the presence of oxygen with carbon or sometimes without the presence of oxygen.
6) Discuss the different methods used to prevent corrosion.
Ans: – There are various methods that are used for the prevention of the metal from the corrosion which are –
- Galvanization is the main process.
- By using zinc coating.
- Making alloys.
7) In the purification of a metal (M), what all will act as anode, cathode and electrolyte. Explain with an example.
Ans: – The purification is used for the extracting the metal from the ore. For example, coper purification.
For anode: – impure metal (impure copper)
For cathode: – pure metal (pure copper).
8) Explain the following techniques used in concentration of ore:
(i) Gravity separation method
(ii) Froth flotation method
(iii) Magnetic separation method.
Ans: – (i) There are different metal impurities present in the ore. So, we need to separate the different gravity metal impurities by this process. The specific gravity is different of the impurities which are removed according to their gravity.
(ii) In a froth flotation method there are various steps are required. At first the metal is crushing this metal. Then this metal is grinding to extracted from the ore. The various metal is extracted by this.
(iii) The different magnetic material is present in an ore. The metal which are addicted to magnet are separates from the other metal. The non-magnetic material which are separately placed in the other places. By this method the different magnetic material is separated.
9) Discuss the extraction of iron from hematite as per the following steps:
(i) Concentration of ore
(ii) Reduction of oxide to metal (along with chemical equation)
(iii) Diagram of blast furnace.
Ans: –
10) Explain the electrochemical principle behind corrosion.
Ans: – Metal which present in an open placefor keeping so many days in there this metal are came in contact with the moisture. After reacting with the moisture there produced a layer on the metal. This layer is removed by the galvanization method. For this there will be layer of the different alloy which prevent it to react with the moisture.
11) Give reasons for:
(i) Gold, silver and platinum are used in making jewellery.
Ans: – This gold, silver, platinum is less reactive as a result we see these elements doesn’t react with present different gases in air. As well as these metals are also very ductile in nature so various shape are be formed by this metal.
(ii) Sodium, potassium and lithium metals are stored under kerosene.
Ans: – As we all know that in presence of air the sodium, potassium and lithium react with the other gases. For this reason,these elements are kept in kerosene. This element creates a flammable reaction by keeping it in air.
(iii) Although aluminium is an active metal it is still used to prepare cooking utensils.
Ans: – The high melting point and the high conductivity of the aluminium are the main reason for the making of utensil. The conductivity of heat gave the benefits to the aluminium for making pressure cooking utensils.
(iv) Carbonate and sulphide ores are converted into their oxides for extraction of metal.
Ans: – The carbonate and sulphide ores are converted into their oxides for extraction of the metal as it is easier to extracted the metal from them easily. These ores are easily reacted with the present air and by reduction process metal is extracted. And for this reason, we see most of the metal are present in in its sulphide and carbonate ores.
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