What happens when halogenoalkanes react with aqueous sodium hydroxide?

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Multiple Choice

What happens when halogenoalkanes react with aqueous sodium hydroxide?

Explanation:
The main idea is nucleophilic substitution: hydroxide ion acts as a strong nucleophile and replaces the halogen on the haloalkane. In aqueous NaOH, the OH- attacks the carbon attached to the halogen, the halogen leaves as X−, and a C–O bond forms, giving an alcohol (R–OH) along with the sodium halide (NaX) as a by-product. For less hindered (primary or secondary) haloalkanes this happens readily via SN2; for highly substituted (tertiary) haloalkanes an SN1 pathway can also lead to the same alcohol product under these conditions. Under some conditions, such as hot, concentrated base, elimination to an alkene could compete, but with standard aqueous NaOH the substitution to alcohol is the dominant outcome.

The main idea is nucleophilic substitution: hydroxide ion acts as a strong nucleophile and replaces the halogen on the haloalkane. In aqueous NaOH, the OH- attacks the carbon attached to the halogen, the halogen leaves as X−, and a C–O bond forms, giving an alcohol (R–OH) along with the sodium halide (NaX) as a by-product. For less hindered (primary or secondary) haloalkanes this happens readily via SN2; for highly substituted (tertiary) haloalkanes an SN1 pathway can also lead to the same alcohol product under these conditions. Under some conditions, such as hot, concentrated base, elimination to an alkene could compete, but with standard aqueous NaOH the substitution to alcohol is the dominant outcome.

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