Chemistry - Halogen Derivative Question with Solution | TestHub

Question Explanation:

Match each reaction with the correct substitution product formed by strong nucleophiles.

Concept:

This question is based on nucleophilic substitution $\left({\mathrm{S}}_{\mathrm{N}}2\right)$ reactions.

Solution:

A) Ethoxide $\left({\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}\right)$is strong nucleophile

• It attacks the methyl group via ${\mathrm{S}}_{\mathrm{N}}2$ to form an ether (Williamson synthesis). The product is ${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{C}}_2{\mathrm{H}}_5$.

B) ${\mathrm{PH}}_3$ itself is a nucleophile and can undergo ${\mathrm{S}}_{\mathrm{N}}2$ reactions.

• Nucleophilic attack on primary alkyl iodide yields alkyl phosphine (${\mathrm{CH}}_3{\mathrm{CH}}_2-{\mathrm{PH}}_2$).

C) Sodium acetylide ($\mathrm{HC}\equiv {\mathrm{C}}^{-}$) is a strong nucleophile.

• It attacks primary ethyl bromide via ${\mathrm{S}}_{\mathrm{N}}2$ to give $\mathrm{HC}\equiv \mathrm{C}-{\mathrm{CH}}_2{\mathrm{CH}}_3$.

D) Methoxide (${\mathrm{CH}}_3{\mathrm{O}}^{-}$) is a strong nucleophile.

• An ${\mathrm{S}}_{\mathrm{N}}2$ attack on methyl chloride gives dimethyl ether (${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{CH}}_3$).

Final Answer: A $\to$ q, B $\to$ p, C $\to$ s, D $\to$ r