1) Copper sulfate solution reacts with KCN to give A) $Cu(CN)_{2}$ B) CuCN C) $ K_{2}[Cu(CN)_{4}]$ D) $K_{3}[Cu(CN)_{4}]$ Answer: Option DExplanation:$CuSO_{4} + 2KCN \rightarrow Cu(CN)_{2} + K_{2}SO_{4}$ $2Cu(CN)_{2} \rightarrow Cu_{2} (CN)_{2}$ OR $2CuCN+CN-CN_{cyanogen}$ $CuCN+ 3KCN \rightarrow K_{3}[Cu(CN)_{4}]_{Colourless}$
