The precipitate of which of the following compounds is soluble in excess of ammonia solution?

Options

A. Iron(II) chloride
B. Magnesium chloride
C. Copper(II) sulphate
D. Lead nitrate

Answer

C

Explanation

When `NH_4OH` solution is added drop by drop to copper sulphate solution a pale blue or bluish white precipitate is formed which is soluble in excess of `NH_4OH` and deep blue or inky blue solution is formed.
`CuSO_4 + 2NH_4OH to Cu(OH)_2 + (NH_4)_2 SO_4`
`Cu(OH)_2 + 4NH_4OH to Cu(NH_3)_4 (OH)_2 + 4H_2O`