To a salt solution 'Y' a small quantity of NH₄OH solution is added slowly and then in excess. A pale blue precipitate is formed which dissolves in ex­cess to form a clear inky blue solution. Identify the posi­tive ion in the salt 'Y'

State your observations when ammonium hydroxide solution is added drop by drop and then in excess to each of the following:

(i) copper sulphate solution

(ii) zinc sulphate solution.

How will you distinguish between — Ammonium Hydroxide & Sodium Hydroxide using CuSO₄

Choose the correct answer from the options given :

The salt solution which does not react with ammonium hydroxide is :

1. Calcium nitrate
2. Zinc nitrate
3. Lead nitrate
4. Copper nitrate