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Chemical Industries: MCQs with answer and explanation

1. The naturally occuring metallic compounds are called as:





... Answer is c)
Explanation: Mostly, metals exist in combined state (in compound form) with other elements rather than in free state with few exception. These compounds of metals are known as minerals. For example, iron exists as haematites (Fe2O4) and magnetsite (Fe4O4. Haematites (Fe2O4) and magnetsite (Fe4O4 are minerals of iron.

2. The separation of minerals from gangue is called concentration. Which of the following methods is used for concentration?





... Answer is d)
Floatation: Floatation is the process in which ore particles are agitated with mixture of oil and detergents. Mineral particles rise on the top as froth, from where it is sepearated. Copper ore is generally concentrated by this method.

3. Which of the following steps is not used in the extraction process of metals





... Answer is c)
Explanation: Floatation is the process which is used for concentration of ore. In extraction process, metals are first oxidized and then reduced.

4. In electrofining of copper, ----------------- is used as anode





... Answer is b)
Explanation: In electrolytic cell, impure copper is used as anode because at anode oxidation takes place. As copper is oxidized to Cu+2, it enters the electrolytic solution. At the cathode, Cu+2 is reduced and deposited a pure copper.

5. Which of the following is not a raw material for manufacture of soda ash





... Answer is b)
Explanation: Raw materials required for manufacturing of the soda ash include: i. brine ii. ammonia iii. lime stone .

6. A mixture of Cu2S and FeS called matte is produced in one of the metallergical operations in the extraction of copper. The name of this operation is





... Answer is c)
Explanation: In bessemeriztion, cuprous sulphide (Cu2S)is oxidized to cuprous oxide (Cu2O) which reacts with remaining cuprous sulphide (Cu2S) to form metallic copper.

7. Chemical formula of slaked lime is:





... Answer is c)
Explanation: Chemical formula of slaked lime is Ca(OH)2. Chemical formulae of lime stone and lime are CaCO3 and CaO, respectively.

8. Calcination is the process in which sodium hydrogen carbonate is heated to get sodium carbonate. Which is not obtained in this process?





... Answer is B)
Explanation: During calcination, CO2, Na2CO3 and H2O are obtained as product.

9. Percentage of nitrogen in ureas is





... Answer is d)
Explanation: % N = (Molar mass of N in urea/ Molar mass of Urea)× 100 = (28 /64)× 100 = 46.6%

10. What happes when ammonium carbamate is distilled with steam?





... Answer is d)
Explanation: When ammonium carbamate is distilled with steam, urea solution is produced.       

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