1. (RCOO)₂Mg 2. RCOO^(-M)g^+X 3. R₃CO^(-M)g^+X 4. RCOO^(-X)^+

Answer: 2. RCOO^(-M)g^+X Key idea: a Grignard reagent adds to CO₂ to give a magnesium carboxylate salt, which acid hydrolysis converts to the acid. mathrmRMgX + O=C=O → RCOO^(-M)g^+X (Y), then H₃O^+ gives RCOOH . Y is the halomagnesium carboxylate, option 2. Option 1 would need two carboxylate groups on one Mg, but one RMgX adds to one CO₂ , and option 3 is what a ketone would give after further addition.

Topic: Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen)· Organic Compounds Containing Oxygen

RMgX + CO_2 dry ether Y H_3O^+ RCOOHWhat is Y in the above reaction ?

1. \((RCOO)_2Mg\)

2. \(RCOO^-Mg^+X\)

3. \(R_3CO^-Mg^+X\)

4. \(RCOO^-X^+\)

Doubtly Asked 30 Oct 2026 NEET UG 2022 Practice test neet Save WhatsApp Report

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Answer: 2. \(RCOO^-Mg^+X\)

Key idea: a Grignard reagent adds to \(\mathrm{CO_2}\) to give a magnesium carboxylate salt, which acid hydrolysis converts to the acid.

\(\mathrm{RMgX + O{=}C{=}O \to RCOO^-Mg^+X}\) (Y), then \(\mathrm{H_3O^+}\) gives \(\mathrm{RCOOH}\).

Y is the halomagnesium carboxylate, option 2. Option 1 would need two carboxylate groups on one Mg, but one \(\mathrm{RMgX}\) adds to one \(\mathrm{CO_2}\), and option 3 is what a ketone would give after further addition.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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RMgX + CO_2 dry ether Y H_3O^+ RCOOHWhat is Y in the above reaction ?

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