Reduction of benzaldehyde with NaBH4 gives which product?

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Multiple Choice

Reduction of benzaldehyde with NaBH4 gives which product?

The key idea is that sodium borohydride (NaBH4) is a mild reducing agent that donates a hydride to carbonyl groups, turning aldehydes into primary alcohols. When benzaldehyde (an aldehyde) reacts with NaBH4, the carbonyl carbon is attacked by a hydride, the C=O becomes an O– that is then protonated to give the alcohol. The phenyl ring stays intact, so the product is benzyl alcohol (phenylmethanol), not benzaldehyde itself or any hydrocarbon. The other options would require removing the oxygen entirely or introducing a halogen, which NaBH4 does not do under these conditions.

The key idea is that sodium borohydride (NaBH4) is a mild reducing agent that donates a hydride to carbonyl groups, turning aldehydes into primary alcohols. When benzaldehyde (an aldehyde) reacts with NaBH4, the carbonyl carbon is attacked by a hydride, the C=O becomes an O– that is then protonated to give the alcohol. The phenyl ring stays intact, so the product is benzyl alcohol (phenylmethanol), not benzaldehyde itself or any hydrocarbon. The other options would require removing the oxygen entirely or introducing a halogen, which NaBH4 does not do under these conditions.

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