Copper sulphate solution reacts with $\mathrm{KCN}$ to give

• A

  $\mathrm{Cu}(\mathrm{CN})_{2}$
• B

  $\mathrm{CuCN}$
• C

  $\mathrm{K}_{2}\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]$
• Correct answer
  D

  $\mathrm{K}_{3}\left[\mathrm{Cu}(\mathrm{CN})_{4}\right]$

Solution

$\mathrm{CuSO}_{4}+2 \mathrm{KCN} \rightarrow \mathrm{Cu}(\mathrm{CN})_{2}+\mathrm{K}_{2} \mathrm{SO}_{4}$ $2 \mathrm{Cu}(\mathrm{CN})_{2} \rightarrow \mathrm{Cu}_{2}(\mathrm{CN})_{2}$ or

Hence, the correct answer is option: 'D'.