Copper sulphate dissolves in excess of KCN to give

Question

Copper sulphate dissolves in excess of KCN to give (A) CuCN (B) [Cu(CN)4]3- (C) [Cu(CN)4]2- (D) Cu(CN)2

Tardigrade Admin · Accepted Answer

When copper sulphate dissolves in potassium cyanide, then following reaction takes place:-

C u S O_{4} + 2 K CN \to K_{2} S O_{4} + C u (CN)_{2}

Now, since

C u (CN)_{2}

is unstable, it undergoes decomposition as:-

C u (CN)_{2} \to C u CN + (CN)_{2}

N o w, C u CN + 3 K CN \to K_{3} [C u (CN)_{4}]

that is

[C u (CN)_{4}]^{3 -}

Q. Copper sulphate dissolves in excess of $K CN$ to give