JEE Main 2026 Apr 6 Shift 1, Chemistry Q15: Preparation of Alkanes

JEE Main2026Apr 6, Shift 1Chemistry

Given below are two statements:

Statement-I: Methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of sodium acetate and reaction of $CH_{3} MgBr$ with water.

Statement-II: Methane cannot be prepared from unsaturated hydrocarbons and by Wurtz reaction.

In the light of the above statements, choose the correct answer from the options given below.

A
Both Statement-I and Statement-II are true.
B
Both Statement-I and Statement-II are false.
C
Statement-I is true but Statement-II is false.
D
Statement-I is false but Statement-II is true.

Solution

Statement-I: Kolbe's electrolysis of sodium acetate produces ethane (via coupling of two methyl radicals), not methane. So this statement contains a false claim. False.

(Decarboxylation of $CH_{3} COONa$ with soda-lime does give methane, and $CH_{3} MgBr + H_{2} O$ does give methane, but the inclusion of Kolbe's electrolysis is incorrect.)

Statement-II: Wurtz reaction couples two alkyl halides $2 R-X + 2 Na \to R-R$ , so starting from $CH_{3} X$ gives ethane, not methane. Methane also cannot be obtained from unsaturated hydrocarbons by hydrogenation (those give larger alkanes). True.

$∴$ Statement-I is false, Statement-II is true.

Concept behind this question

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