See image — Reaction Mechanism Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the starting material: The starting material is chlorocyclohexane (cyclohexyl chloride), a cyclohexane ring bearing a -Cl substituent on one of its carbons. Step 2 - Formation of Grignard reagent (A): Treatment of chlorocyclohexane with Mg in diethyl ether (Et2O) forms the Grignard reagent cyclohexylmagnesium chloride (C6H11MgCl). This is compound (A). Step 3 - Reaction with formaldehyde (CH2O): The Grignard reagent (a strong nucleophile) attacks formaldehyde (CH2O, the simplest aldehyde) in a nucleophilic addition reaction. The cyclohexyl carbanion attacks the carbonyl carbon of CH2O, forming a magnesium alkoxide intermediate: C6H11-CH2-OMgCl. Step 4 - Acid workup (H3O+): Protonation of the magnesium alkoxide with aqueous acid (H3O+) yields the primary alcohol: cyclohexyl-CH2-OH, i.e., cyclohexanemethanol (also called cyclohexylmethanol). This is compound (B). Step 5 - Structure of product (B): The product is a cyclohexane ring with a -CH2OH group attached directly to it — a primary alcohol with one extra carbon (from CH2O) inserted between the ring and the OH group. Step 6 - Matching to options: - Option (a) shows a structure where OH is directly on the ring carbon (secondary alcohol), which would result from reaction with a carbonyl compound other than formaldehyde, or is drawn as a cyclopentane variant — does not match. - Option (b) shows cyclohexane with -CH2OH attached — this matches the expected product (cyclohexylmethanol). - Option (c) shows two cyclohexane rings, which would require a different starting material — does not match. - Option (d) shows cyclohexene, a dehydration product — not formed under these conditions. Therefore, the correct answer is B.