Concept:Primary alcohols oxidize sequentially: first to an aldehyde, and then immediately to a carboxylic acid if left in the oxidizing environment.
Solution:- Dichromate is a strong oxidizing agent.
- Once the primary alcohol is oxidized to an aldehyde, the aldehyde itself is extremely susceptible to further oxidation.
- To prevent the aldehyde from converting completely into a carboxylic acid, it must be removed from the reaction mixture immediately.
- Since aldehydes have lower boiling points than their parent alcohols and the resulting acids (due to lack of hydrogen bonding), they can be selectively boiled off (distilled) as soon as they form.
Why other options are incorrect:Aldehydes do not spontaneously decompose back to alcohols (oxidation is not easily reversible here). Aldehydes cannot be oxidized to ketones because the carbonyl is at the end of the chain, so it strictly forms a carboxylic acid.
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