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When copper (ii) sulphate solution is treated with excess...

When copper (ii) sulphate solution is treated with excess ammonium hydroxide, a precipitate is first formed, and then this dissolves to give a deep blue solution.

This deep blue solution is a?

A.

Cu(OH)2

B.

CuSo4.5H2O

C.

(NH4)2SO4

D.

Cu(NH3)4(OH)2

E.

CuSO4.(NH4)2SO4.2H2O

Correct answer is D

CuSO4+2NH4OH(NH4)2SO4+Cu(OH)2(pale−blue)

The pale blue precipitate of copper hydroxide dissolves in excess of ammonium hydroxide forming tetraamine copper [II] sulphate, an azure blue(deep blue) soluble complex salt.

Cu(OH)2+(NH4)2SO4+2NH4OH[Cu(NH3)4]SO4+4H2O