Concept:Reactivity of carbonyl compounds toward nucleophilic addition is governed by two major factors: Steric hindrance and Electronic (inductive) effects.
Solution:- Steric Factor: Formaldehyde (\( HCHO \)) has only two tiny hydrogen atoms attached to the carbonyl carbon, leaving it completely exposed to nucleophilic attack.
- Electronic Factor: Alkyl groups (like \( -CH_3 \)) are electron-donating (via the +I effect). They push electron density toward the carbonyl carbon, reducing its partial positive charge and thus its electrophilicity.
- Formaldehyde has no alkyl groups, making its carbonyl carbon the most electrophilic.
- Therefore, Formaldehyde is the most reactive of the series.
Why other options are incorrect:Acetaldehyde (\( CH_3CHO \)) has one electron-donating methyl group. Acetone (\( (CH_3)_2CO \)) has two, making it the least reactive of the three due to maximum steric hindrance and electron donation.
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