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Chemistry Question 65 – JEE-MAIN 2026

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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 CH3MgBr 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

Consider the reactants and products of named reactions like decarboxylation, Kolbe's electrolysis, and Wurtz reaction.

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Ninja Strategy•Identify Key Reaction Products

Quickly recall the products of Kolbe's electrolysis (ethane from acetate) and Wurtz reaction (higher alkanes from methyl halides) to determine the truthfulness of each statement.

Step 1: Evaluate Statement I✦ Active

Statement I claims methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of sodium acetate, and reaction of CH3MgBr with water. Let's analyze each method:

1. Decarboxylation of sodium ethanoate (sodium acetate): CH3COONa+NaOH→CaO,ΔCH4+Na2CO3. This method correctly yields methane.

2. Kolbe's electrolysis of sodium acetate: 2CH3COONa+2H2O→electrolysisCH3−CH3+2CO2+2NaOH+H2. This method yields ethane (CH3−CH3), not methane (CH4). This part makes Statement I incorrect.

3. Reaction of CH3MgBr (methyl magnesium bromide) with water: CH3MgBr+H2O→CH4+Mg(OH)Br. This method correctly yields methane.

Since Kolbe's electrolysis of sodium acetate does not produce methane, Statement I is **false**.

Step 2: Evaluate Statement II○ Expand

Statement II claims methane cannot be prepared from unsaturated hydrocarbons and by Wurtz reaction. Let's analyze each part:

1. Preparation from unsaturated hydrocarbons: Unsaturated hydrocarbons (alkenes, alkynes) typically contain at least two carbon atoms. Direct conversion of an unsaturated hydrocarbon to methane (a one-carbon alkane) is not possible. For example, hydrogenation of ethene (CH2=CH2) yields ethane (CH3−CH3), not methane.

2. Preparation by Wurtz reaction: The Wurtz reaction involves coupling two alkyl halides (2RX+2Na→dry etherR−R+2NaX). If methyl halide (CH3X) is used, the product is ethane (CH3−CH3), not methane. Therefore, methane cannot be prepared by Wurtz reaction.

Both parts of Statement II are correct. Therefore, Statement II is **true**.

Step 3: Combine Conclusions○ Expand

Based on the analysis, Statement I is false, and Statement II is true. This corresponds to option 4.

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