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Alcohols are classified as primary (1°), secondary (2°), or tertiary (3°) based on:
AThe boiling point
BThe number of alkyl/aryl groups attached to the carbon bearing the -OH
CThe number of -OH groups
DThe number of hydrogens in the molecule
Answer & Solution
Correct answer: B. The number of alkyl/aryl groups attached to the carbon bearing the -OH
**Classification by carbon bearing -OH**: 1° (one C-substituent + 2 H's), 2° (two C-substituents + 1 H), 3° (three C-substituents + no H). E.g., CH₃CH₂OH = 1°; (CH₃)₂CHOH = 2°; (CH₃)₃COH = 3°. This classification determines reactivity (Lucas test, SN1/SN2 behaviour, dehydration ease, oxidation product type).
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