Carboxylic Acids Question 53
Question: Which of the following acids has the smallest dissociation constant
[IIT-JEE (Screening) 2002]
Options:
A) $ CH_3CHFCOOH $
B) $ FCH_2CH_2COOH $
C) $ BrCH_2CH_2COOH $
D) $ CH_3CHBrCOOH $
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Answer:
Correct Answer: C
Solution:
$ BrCH_2CH_2COOH $ is least acidic or has less $ K _{a} $ i.e., dissociation constant. It is A due to lesser -I effect of Br than F and B Br atom further away form $ -COOH $ group.