A Levels Chemistry (9701)•9701/11/M/J/23
Explanation
Esterification requires alcohol and carboxylic acid Steps:
- Ester Z forms via acid-catalyzed reaction of alcohol and carboxylic acid.
- All options include CH3CH2OH (ethanol, an alcohol).
- The partner compound must be a carboxylic acid to produce an ester with H2SO4 catalyst.
- Option C pairs ethanol with CH3CH2CH2COOH (butanoic acid), yielding ester Z as CH3CH2CH2COOCH2CH3.
Why C is correct:
- Ethanol and butanoic acid undergo Fischer esterification: RCOOH + R'OH ⇌ RCOOR' + H2O, forming the specified ester Z.
Why the others are wrong:
- A: CH3COOH (acetic acid) forms ethyl acetate (CH3COOCH2CH3), not ester Z.
- B: CH3COCH3 (acetone, a ketone) forms acetal or no reaction, not an ester.
- D: CH3OCH2CH2OH (another alcohol) yields no carboxylic acid, so no ester forms.
Final answer: C
Topic: Carboxylic acids and derivatives
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