A mixture of `Cu^(2+) and Ni^(2+)` can be separated for identification by

Options

A. passing `H_2 S` in acidic medium
B. passing `H_2 S` in alkaline medium
C. passing `H_2 S` in neutral medium
D. passing `H_2 S` in dry mixture

Answer

A

Explanation

By passing `H_2 S` gas in acidic medium in a mixture of `Cu^(2+)` and `Ni^(2+)`, only `Cu^(2+)` will be precipitated as CuS. `Ni^(2+)` will not be precipitated because its sulphide has much higher value of solubility product.