Chemistry - Halogen Derivative Question with Solution | TestHub

Question Explanation:

Match each reaction with its correct reaction mechanism.

Concept:

This question is based on  $S{N}^i,S{N}^2,E_2,S{N}^1$ mechanisms in alcohol/halide reactions.

Solution:

(A) $\mathrm{ROH}+{\mathrm{SOCl}}_2$ (no pyridine)

• Proceeds via SNⁱ (internal nucleophilic substitution).

• Retention of configuration.

(B)$\mathrm{ROH}+{\mathrm{SOCl}}_2+$ pyridine

• Converts OH to Cl via SN² .

• Inversion of configuration.

(C) 2° alkyl bromide + strong base (alcoholic)

• Strong base + secondary halide favors E2 elimination .

• Single-step, no intermediates.

(D) 3° alcohol + HCl

• Protonation → carbocation → chloride attack.

• Classic SN¹ mechanism → racemization.

Final Answer: A → r, B → q, C → s, D →p