Ketones are comparatively less reactive than aldehdye. It is due to_______________?
Correct answer: C. Both A and B
- A. alkyl groups are electron donating
- B. steric hindrance
- C. Both A and B
- D. none
Explanation
Ketones are less reactive because two alkyl groups donate electron density toward the carbonyl carbon, reducing its positive character, and they also create greater steric hindrance to nucleophilic attack. Therefore both effects in options A and B operate, making C correct. A student may choose A alone by remembering only the electron-donating effect and overlooking the physical crowding around the carbonyl group.
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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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