Chemistry Carboxylic Acids ETEA 2022
PMDC Verified Question 46 of 94
Which of the following statements is false about the acid-strength of acetic acid?
A
Acetic acid is a stronger acid than monochloroacetic acid
B
Acetic acid is a stronger acid than Propionic acid.
C
Acetic acid is a weaker acid than trichloroacetic acid
D
Acetic acid is a weaker acid than formic acid
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Acetic acid is a stronger acid than monochloroacetic acid
Concept:

Adding an electron-withdrawing halogen (like chlorine) to a carboxylic acid dramatically increases its acidity via the inductive (\( -I \)) effect. Conversely, adding electron-donating alkyl groups decreases acidity.

Solution:

  • Let's evaluate the truth of each statement.


  • Option B: True. Acetic acid is stronger than propionic acid (ethyl group has stronger \( +I \) than methyl).


  • Option C: True. Trichloroacetic acid is vastly stronger due to 3 chlorines.


  • Option D: True. Formic acid has no methyl group destabilizing its anion, so it is stronger than acetic acid.


  • Option A: False. Monochloroacetic acid has a chlorine atom pulling electron density, making it stronger than unsubstituted acetic acid. The statement claims acetic is stronger, which is a lie.


Why other options are incorrect:

Options B, C, and D state experimentally verifiable facts. The question specifically asks for the false statement.

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