In SN2 displacement of ethyl bromide by cyanide, which nitrile is formed?

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Multiple Choice

In SN2 displacement of ethyl bromide by cyanide, which nitrile is formed?

SN2 displacement of a primary alkyl halide by cyanide replaces the leaving group with the CN group, keeping the carbon framework intact. Ethyl bromide is CH3-CH2-Br, a primary substrate, so CN− attacks the carbon bearing bromine and Br− leaves. This gives CH3-CH2-CN, which is propionitrile. The other nitriles would require different starting materials (methyl, benzyl/aryl, or butyl halides), so they don’t arise from ethyl bromide.

SN2 displacement of a primary alkyl halide by cyanide replaces the leaving group with the CN group, keeping the carbon framework intact. Ethyl bromide is CH3-CH2-Br, a primary substrate, so CN− attacks the carbon bearing bromine and Br− leaves. This gives CH3-CH2-CN, which is propionitrile. The other nitriles would require different starting materials (methyl, benzyl/aryl, or butyl halides), so they don’t arise from ethyl bromide.

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