In an SN2 reaction, ethyl bromide treated with cyanide yields which nitrile?

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Multiple Choice

In an SN2 reaction, ethyl bromide treated with cyanide yields which nitrile?

In SN2 substitution, a cyanide ion attacks the carbon bearing the leaving group and replaces it, giving a nitrile where the R group from the alkyl halide remains attached to the nitrile carbon. Ethyl bromide has an ethyl (two-carbon) R group, so when CN− substitutes Br, you form propionitrile (CH3–CH2–CN). The cyanide carbon becomes the nitrile carbon, and the ethyl group stays attached to it. That’s why the product is propionitrile. The other nitriles would require different starting alkyl halides (methyl, benzyl, or longer chains), not ethyl bromide.

In SN2 substitution, a cyanide ion attacks the carbon bearing the leaving group and replaces it, giving a nitrile where the R group from the alkyl halide remains attached to the nitrile carbon. Ethyl bromide has an ethyl (two-carbon) R group, so when CN− substitutes Br, you form propionitrile (CH3–CH2–CN). The cyanide carbon becomes the nitrile carbon, and the ethyl group stays attached to it. That’s why the product is propionitrile. The other nitriles would require different starting alkyl halides (methyl, benzyl, or longer chains), not ethyl bromide.

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