When `NH_4OH` is added to copper sulphate solution, blue colour is obtained due to formation of

Options

A. `Cu^(2^+)`
B. `Cu(NH_4 SO_4)`
C. `[Cu(NH_3)_4]^(2^+)`
D. `Cu(OH)_2`

Answer

C

Explanation

Precipitate of Cu(OH), is formed which dissolves in excess of ammonia solution dire to formation of soluble blue complex
`CuSO_4 + 2NH_4O rarr Cu(OH)_2 + (NH_4)_2SO_4`
`Cu(OH)_2, + 2NH_4OH+ (NH_4)_2 SO_4 rarr Cu(NH_3)_4 SO_4 + 4H_2O`