Concept:Aldehydes are highly susceptible to oxidation and are readily converted into their corresponding carboxylic acids (maintaining the same number of carbon atoms) when treated with strong oxidizing agents.
Formula:$$ \text{HCHO} + [\text{O}] \xrightarrow{\text{K}_2\text{Cr}_2\text{O}_7 / \text{H}_2\text{SO}_4} \text{HCOOH} $$
Solution:- Formaldehyde (\( \text{HCHO} \)) contains exactly one carbon atom.
- Acidified potassium dichromate is a strong oxidizing agent.
- It inserts an oxygen atom into the aldehydic \( \text{C-H} \) bond, creating a carboxyl group (\( -\text{COOH} \)).
- The 1-carbon carboxylic acid formed is methanoic acid (formic acid).
Why other options are incorrect:Methanol would require reduction. Acetone (3 carbons) and Acetaldehyde (2 carbons) are impossible to form without adding carbon atoms to the framework.
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