Identify the cation present in each of the following compounds — W, X, Y, Z :
1. To solution ‘W’, ammonium hydroxide is added in minimum quantity first and then in excess. A dirty white precipitate is formed which dissolves in excess to form a clear solution.
2. To solution ‘X’ ammonium hydroxide is added in minimum quantity first and then in excess. A pale blue precipitate is formed which dissolves in excess to form a clear inky blue solution.
3. To solution ‘Y’ a small amount of sodium hydroxide is added slowly and then in excess. A white insoluble precipitate is formed.
4. To a salt ‘Z’ calcium hydroxide solution is added and then the mixture is heated. A pungent smelling gas turning moist red litmus paper blue is obtained.
