Oxidation of a primary alcohol with acidified potassium dichromate, distilling the product as it forms, gives
Correct answer: B. an aldehyde
- A. a ketone
- B. an aldehyde
- C. a carboxylic acid
- D. an alkene
Explanation
Distilling removes the aldehyde as soon as it is produced, before it can be oxidised further, whereas heating under reflux keeps it in the flask and the reaction continues to the carboxylic acid. The orange dichromate turns green as chromium is reduced from plus 6 to plus 3. Secondary alcohols stop at the ketone, since no hydrogen remains on the carbonyl carbon.
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About Alcohols
Alcohols contain a hydroxyl group attached to a saturated carbon atom and are classified as primary, secondary or tertiary. Their nomenclature, hydrogen bonding, acidity, oxidation, dehydration, reaction with sodium and conversion to haloalkanes are covered, along with the distinction between alcohols and phenols, where the hydroxyl group is attached directly to an aromatic ring.
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535 free Alcohols and Phenols MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
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