Nitrile intermediate in Grignard ketone synthesis Steps:

• Target is butan-2-one (CH3CH2COCH3), a methyl ketone from ethyl bromide (CH3CH2Br).
• Standard two-step route: convert alkyl halide to nitrile via SN2 with CN-, then add methyl Grignard.
• First step yields CH3CH2CN; second step is CH3CH2CN + CH3MgBr, followed by H3O+ hydrolysis.
• Check options: only CH3CH2CN fits as direct first-stage product leading to target.

Why C is correct:

• CH3CH2CN + CH3MgBr gives imine intermediate that hydrolyzes to CH3CH2COCH3 (standard organometallic addition to nitriles forms ketones).

Why the others are wrong:

• A: CH3CH2OH (from hydrolysis) leads to aldehydes/acids or ethers, not direct ketone in one step.
• B: CH3CH2CHO (from oxidation/multi-steps) + CH3MgBr yields CH3CH2CH(OH)CH3 alcohol, not ketone.
• D: CH3CH2CH3 (from reduction) is inert alkane, unreactive for ketone formation in one step.

Final answer: C