A) \[{{\text{K}}_{2}}[Cu{{(CN)}_{4}}]\]
B) \[{{K}_{3}}[Cu{{(CN)}_{4}}]\]
C) \[CuC{{N}_{2}}\]
D) \[Cu[K\,Cu{{(CN)}_{4}}]\]
Correct Answer: B
Solution :
\[\text{CuS}{{\text{O}}_{\text{4}}}\]reacts with KCN and gives a white precipitate of cuprous cyanide and cyanogen gas. The cuprous cyanide dissolves in excess of KCN forming \[{{\text{K}}_{3}}[Cu{{(CN)}_{4}}].\] \[CuS{{O}_{4}}+2KCN\xrightarrow{{}}{{K}_{2}}S{{O}_{4}}+Cu{{(CN)}_{2}}\] \[2Cu{{(CN)}_{2}}\xrightarrow{{}}\underset{\text{insoluble}}{\mathop{2CuCN}}\,+\underset{\text{cyanogen}}{\mathop{CN-CN}}\,\] \[CuCN+3KCN\xrightarrow{{}}\underset{\text{soluble}}{\mathop{{{K}_{2}}[Cu(C{{N}_{4}})]}}\,\]You need to login to perform this action.
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