A Levels Chemistry (9701)•9701/13/O/N/22

Explanation
Elimination favored in ethanolic NaOH
Steps:
- Ethanolic NaOH acts as a strong base in alcohol solvent, promoting elimination over substitution.
- 2-Bromopropane is a secondary alkyl halide, prone to E2 mechanism.
- In E2, beta-hydrogen is abstracted, and Br leaves, forming a double bond.
- The product is propene (CH3-CH=CH2) via dehydrohalogenation.
Why D is correct:
- Alcoholic NaOH induces E2 elimination per Zaitsev's rule, yielding the most stable alkene, propene, as the major product.
Why the others are wrong:
- A: Propan-1-ol requires SN2 on primary halide; secondary favors elimination.
- B: Propan-2-ol from SN1 substitution, but ethanolic conditions suppress nucleophilic attack.
- C: 2-Hydroxypropane names propan-2-ol, incorrect for elimination pathway.
Final answer: D
Topic: Halogen compounds
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