Chemistry Aldehydes & Ketones MDCAT 2019
PMDC Verified Question 61 of 94
Which of the following will give a positive test with Tollen's reagent?
A
Tertiary Alcohols
B
Ketones
C
Aldehydes
D
Carboxylic Acids
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Aldehydes
Concept:

Tollens' reagent is a mild oxidizing agent (ammoniacal silver nitrate).

Solution:

  • Because aldehydes possess a hydrogen atom bonded directly to the carbonyl carbon, they are easily oxidized to carboxylic acids.


  • This oxidation provides the electrons necessary to reduce the silver ions in Tollens' reagent, yielding the positive "silver mirror" test.


Why other options are incorrect:

Ketones lack the hydrogen on the carbonyl carbon and cannot be oxidized by mild agents. Tertiary alcohols strongly resist oxidation entirely. Carboxylic acids are already fully oxidized at the carbonyl carbon.

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