An organic compound which liberate carbon(iv)oxide from trioxocarbonate(iv) solution is likely to be?

Step 1: Analyze the question The question asks which organic compound reacts with a trioxocarbonate(IV) solution (a carbonate such as Na₂CO₃, or a hydrogen carbonate) to release carbon(IV) oxide (CO₂) gas.

Step 2: The concept Carbonates and hydrogen carbonates react with acids to release CO₂. So the organic compound must be acidic. In organic chemistry, the group that makes a compound acidic enough to do this is the carboxyl group (-COOH), found in carboxylic acids (alkanoic acids).

General reaction:

2RCOOH + Na₂CO₃ → 2RCOONa + H₂O + CO₂↑

Step 3: Check each option

• A. C₂H₅OH (ethanol): An alcohol. It is neutral, far too weakly acidic to react with carbonates. No CO₂.
• B. C₃H₄ (propyne): An alkyne. It reacts by addition reactions, not as an acid toward carbonates. No CO₂.
• C. C₆H₆ (benzene): An aromatic hydrocarbon. It is not acidic. No CO₂.
• D. CH₃COOH (ethanoic acid): A carboxylic acid. It reacts with carbonates to give CO₂.

Step 4: Solution

2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂↑

The effervescence (fizzing) observed is CO₂, which turns lime water milky. This is the standard laboratory test for a carboxylic acid.

Correct answer: D. CH₃COOH

Exam tip: Remember "acid + carbonate → salt + water + CO₂". In organic chemistry, only the -COOH group gives this fizzing test. Alcohols, alkynes and benzene will not. It is a favourite JAMB/WASSCE question, so keep it in mind.