Question

1) Identify the products (A) and (B) in the reactions.

RX + AgCN => (A) + AgX
RX + KCN => (B) + KX

2) Tertiary alkyl halides are practically inert to substitution by SN² mechanism because..

Answer with proper explanation please!!​

Answer 1

Answer - 1 :

❖ Reaction - I :

$\star\:\underline{\boxed{\tt{\orange{RX+AgCN\longrightarrow \bf{RNC\:(A)}+AgX}}}}$

❖ Reaction - II :

$\star\:\underline{\boxed{\tt{\blue{RX+KCN\longrightarrow \bf{RCN\:(B)}+KX}}}}$

Explanation :

→ 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 isocynide.

Answer - 2 :

Tertiary alkyl halides are practically inert to substitution by SN² mechanism because in tertiary alkyl halides steric hindrance does not allow substitution by SN² mechanism in which the nucleophile attacks on the carbon atom and the reaction takes place in single step.