Question

Describe the role of
(i) NaCN in the extraction of gold from its ore.
(ii) Cryolite in the extraction of aluminium from pure alumina.
(iii) CO in the purification of Nickel

Answer 1

1) In the metallurgy of gold, gold metal is leached with a dilute solution of NaCN in the presence of air (for O2). The gold metal is then obtained from the product by displacement reaction.
2) it lowers the melting point of the mixture of Al203

Answer 2

1) In the metallurgy of gold, gold metal is leached with a dilute solution of NaCN in the presence of air (for O2). The gold metal is then obtained from the product by displacement reaction.

2) it lowers the melting point of the mixture of