A Levels Chemistry (9701)•9701/12/M/J/18
Explanation
Alkaline hydrolysis of ethyl butanoate yields sodium butanoate and ethanol
Steps:
- Identify ethyl butanoate structure: CH3CH2CH2C(O)OCH2CH3, from butanoic acid and ethanol.
- Recognize reaction as saponification with excess NaOH, breaking ester bond at carbonyl.
- Form products: sodium salt of butanoic acid (CH3CH2CH2COONa) and ethanol (CH3CH2OH).
- Match salt to option C as the carboxylate product.
Why C is correct:
- CH3CH2CH2COONa is the sodium butanoate from the butanoyl group (CH3CH2CH2C(O)-), per saponification: RCOOR' + NaOH → RCOONa + R'OH.
Why the others are wrong:
- A. CH3CH2COONa is sodium propanoate, requiring a propanoyl group (one fewer CH2).
- B. CH3COONa is sodium acetate, from an acetyl group (shorter chain).
- D. CH3CH2OH is the alcohol product but not the carboxylate salt emphasized in alkaline ester hydrolysis.
Final answer: C
Topic: Carboxylic acids and derivatives
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