Chemistry Carboxylic Acids MDCAT 2016
PMDC Verified Question 76 of 94
\( \text{CH}_3\text{COOH} + \text{CH}_3\text{CH}_2\text{OH} \rightleftharpoons \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O} \)
Which one of the following will act as a catalyst in above reaction?
A
\( \text{HNO}_3 \)
B
Acidified potassium dichromate
C
\( \text{H}_2\text{SO}_4 \)
D
\( \text{SOCl}_2 \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: \( \text{H}_2\text{SO}_4 \)
Concept:

Esterification (the reaction between a carboxylic acid and an alcohol) requires a strong acid catalyst to protonate the carbonyl oxygen and act as a dehydrating agent.

Formula:

$$ \text{RCOOH} + \text{R'OH} \xrightarrow{\text{Conc. H}_2\text{SO}_4} \text{RCOOR'} + \text{H}_2\text{O} $$

Solution:

  • Concentrated sulfuric acid (\( \text{H}_2\text{SO}_4 \)) acts as a catalyst by providing \( \text{H}^+ \) ions, which makes the carbonyl carbon more electrophilic.


  • Furthermore, concentrated \( \text{H}_2\text{SO}_4 \) absorbs the water produced in the reaction, driving the equilibrium forward according to Le Chatelier's Principle.


Why other options are incorrect:

Nitric acid (\( \text{HNO}_3 \)) is a strong oxidizing agent and would likely oxidize the alcohol rather than catalyze esterification. Potassium dichromate is also an oxidizer. Thionyl chloride (\( \text{SOCl}_2 \)) converts acids into acid chlorides.

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