Tollens reagent, ammoniacal silver nitrate, gives a silver mirror with
Correct answer: C. aldehydes only
- A. ketones only
- B. both aldehydes and ketones
- C. aldehydes only
- D. neither aldehydes nor ketones
Explanation
An aldehyde still has a hydrogen on the carbonyl carbon, so it is easily oxidised to a carboxylic acid while the silver ions are reduced to metallic silver, which deposits as a mirror on clean glass. A ketone has no such hydrogen, so it resists oxidation and gives no reaction. This is the standard test for distinguishing the two classes.
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About Reactivity of Aldehydes and Ketones
The polar carbonyl group makes aldehydes and ketones undergo nucleophilic addition, reduction and condensation reactions. Aldehydes are generally more reactive and oxidise readily to carboxylic acids, whereas ketones resist mild oxidation; reactions with hydrogen cyanide, sodium bisulfite and 2,4-DNP help identify their behaviour.
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679 free Aldehydes and Ketones MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
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