Question

Consider the following metallurgical processes:

1) Heating impure metal with CO and distilling the resulting volatile carbonyl (b.pt. 43${}^{\circ }$C) and finally decomposing at 150${}^{\circ }$C to 230${}^{\circ }$C to get the pure metal.

2) Heating the sulphide ore in the air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged sulphide.

3) Electrolyzing the molten electrolyte containing $CaC{l}_2$ to obtain the metal.

The processes used for obtaining sodium, nickel and copper are, respectively:

• A. 1, 2 and 3
• B. 2, 3 and 1
• C. 3, 1 and 2
• D. 2, 1 and 3

Answer 1

The correct option is C 3, 1 and 2

Electrolyzing the molten electrolyte (NaCl) containing $CaC{l}_2$ to obtain sodium metal in Down's method. The mixture $CaC{l}_2+KF$ lowers the melting point of NaCl from ${800}^{o}C$ to ${600}^{0}C$. Sodium is obtained at the cathode which is an iron rod. The anode is graphite rod.

Heating impure metal with $CO$ and distilling the resulting volatile carbonyl (b.pt. 43${}^{\circ }$C) and finally decomposing at 150${}^{\circ }$C to 230${}^{\circ }$C to get the pure nickel metal.

Heating the sulphide ore in the air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged sulphide to form copper metal.

$2C{u}_{2}S+3O_2\to 2C{u}_{2}O+2S{O}_{2}2C{u}_{2}O+C{u}_{2}S\to 6Cu+S{O}_2$

This is an example of auto reduction and the process is called Bessemerization.

The processes used for obtaining sodium, nickel and copper are 3, 1, and 2 respectively.