Which of the following alkane cannot be made in good yield by Wurtz reaction ?

1. n-Hexane

2. 2,3-Dimethylbutane

3. n-Heptane

4. n-Butane

Doubtly Asked 30 Oct 2026 NEET UG 2020 Practice test neet Save WhatsApp Report

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Best answer

Answer: 3. n-Heptane

The Wurtz reaction (\(\mathrm{2RX+2Na\rightarrow R-R}\)) gives good yield only when both alkyl groups are the same, so one alkyl halide is used.

n-Butane: from ethyl halide. n-Hexane: from n-propyl halide. 2,3-Dimethylbutane: from isopropyl halide.
n-Heptane has an odd carbon count (7). It would need two different halides (e.g. propyl + butyl), giving a mixture of hexane, heptane and octane.

Answer: option (3).

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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