Cu forms coloured salts while Zn forms colourless salts.

The colour of salt due to

Rock salt is ………..in colour.

Give scientific reasons for the following: When zinc granules are added to copper sulphate solution, the blue coloured solution turns colourless.

Why Zn^(2+) salts are colourless while Ni^(2+) are coloured?

An example for a double salt is

The process due to which greenish coloured conating is formed on brass utensil.

An example of double salt is

Blue coloured copper sulphate crystals become colourless n heating.