The Kolbe’s electrolysis of potassium succinate gives CO2 and _____

A. Ethene

B. Ethane

C. Methane

D. Methanol

In Kolbe's electrolysis, we are dealing with the electrochemical decomposition of carboxylic acids or their salts, which leads to the formation of various products. When potassium succinate undergoes electrolysis, it breaks down into simpler molecules. The key products of this reaction are carbon dioxide (CO2) and a hydrocarbon. To determine which hydrocarbon is produced, let's analyze the structure of potassium succinate and the electrolysis process.

Understanding Potassium Succinate

Potassium succinate is the potassium salt of succinic acid, which has the formula C4H6O4. When subjected to electrolysis, the carboxylate ions (RCOO-) are oxidized at the anode. In the case of potassium succinate, the oxidation leads to the formation of carbon dioxide and a hydrocarbon.

The Electrolysis Process

During the electrolysis, the succinate ions lose electrons and break down. The reaction can be simplified as follows:

• At the anode: RCOO- → CO2 + R-
• At the cathode: R- + H+ → Hydrocarbon

Identifying the Hydrocarbon

In the case of potassium succinate, the hydrocarbon produced is typically a dimerization product of the alkyl radicals formed during the oxidation process. The possible products from the dimerization of the ethyl radical (C2H5) would lead to the formation of ethene (C2H4) or ethane (C2H6).

Analyzing the Options

Now, let’s evaluate the options provided:

• A. Ethene (C2H4) - This is an alkene and could be a product of the reaction.
• B. Ethane (C2H6) - This is an alkane and is also a potential product.
• C. Methane (CH4) - This is unlikely since it would require a different pathway of reduction.
• D. Methanol (CH3OH) - This is not typically formed in Kolbe electrolysis of carboxylates.

Conclusion on the Product

Considering the nature of Kolbe's electrolysis and the structure of potassium succinate, the primary hydrocarbon product formed alongside carbon dioxide is ethene. Therefore, the correct answer to the question is:

A. Ethene

This outcome aligns with the expected results from the electrolysis of carboxylic acids, where the formation of alkenes is common due to the dimerization of alkyl radicals generated during the process.