Question

Identify the products $(A)$ and $(B)$ in the reactions.
$RX + AgCN \rightarrow \frac{ (A)}{ } +Agx$
$RX + KCN \rightarrow \frac{ (B)}{ } +Kx$

• A. $(A) - RCN$, $(B) - RCN$
• B. $(A) - RCN$, $(B) - RNC$
• C. $(A) - RNC$, $(B) - RCN$
• D. $(A) - RNC$, $(B) - RNC$

Answer 1

Answer: (C)

$RX +AgCN \rightarrow\underset{\text{(A)}}{RNC}+AgX$
$RX +KCN \rightarrow \underset{\text{(B)}}{RCN} +KX$
Both $C$ and $N$ can donate electron pairs. Since $KCN$ is predominantly ionic and $C—C$ bond is more stable than $C—N$ bond in case of $KCN$, attack takes place through carbon atom.
$AgCN$ is predominantly covalent hence only nitrogen pair is available for bonding resulting in formation of isocyanide.