Question

When excess of ammonia is added to copper sulphate solutions, the deep blue coloured complex is formed. The complex is

• A. Tetrahedral and paramagnetic
• B. Tetrahedral and diamagnetic
• C. Square planar and diamagnetic
• D. Square planar and paramagnetic

Answer 1

Answer: (D)

Square planar and paramagnetic

Answer 2

$Cu^{2 +} \rightarrow 2OH^{-} \rightarrow Cu(OH)_{2}$

$Cu(OH)_{3} + 4NH_{3} \rightarrow \lbrack Cu(NH_{3})_{4}\rbrack^{2 +}2OH^{-}$

In $\lbrack Cu(NH_{3})_{4}\rbrack^{2 +}$Oxidations state of Cu = +2

$Cu^{2 +}:3d^{9}$

Hybridisations is $dsp^{2}$hence geometry is square planar and paramagnetic due to presence of one unpaired electrons.