See image — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Concept: MOM chloride (methoxymethyl chloride, MeO-CH2-Cl) is a primary alkyl chloride that undergoes SN2 reactions readily. KCN is a source of the cyanide nucleophile (CN⁻). Step 1: Identify the substrate. MOM chloride is ClCH2OCH3 (chloromethyl methyl ether). The chlorine is on a primary carbon bearing an oxygen substituent (alpha to oxygen), making it highly reactive toward SN2. Step 2: Identify the reagent. KCN provides CN⁻, a strong nucleophile and good carbon nucleophile that attacks via carbon in SN2 reactions. Step 3: SN2 mechanism. CN⁻ attacks the carbon bearing the Cl from the back side, displacing Cl⁻. The product is MeO-CH2-CN (methoxymethyl cyanide / methoxy acetonitrile). Step 4: Evaluate options. - Option (a) Cl-CH2-CN: This would require CN⁻ to somehow leave Cl intact, which makes no sense for an SN2 on MOM chloride. - Option (b) MeO-CH2-CN: Direct SN2 substitution of Cl by CN⁻ giving methoxymethyl cyanide. This is correct. - Option (c) Me-O-CH2-CH2-CN: This would require a two-carbon chain, implying an extra CH2 was added, which is not possible in simple SN2. - Option (d) Epoxide with two CN groups: No basis for epoxide formation or double cyanide addition under these conditions. Step 5: The straightforward SN2 substitution of Cl by CN⁻ in MOM chloride gives MeO-CH2-CN. Therefore, the correct answer is B.