The correct order of decreasing acid strength of trichloroacetic acid (A), trifluoroacetic acid
(B) acetic acid
(C) and formic acid
(D) is:

Options

A. I gt II gt III gt IV
B. I gt III gt II gt IV
C. II gt I gt IV gt III
D. II gt IV gt III gt I

Answer

C

Explanation

`underset(pKa = 0.23)(F_(3)C-COOH) > underset(pKa = 0.7)(Cl_3C-COOH) > underset(pKa = 3.75)(H-COOH) > underset(pKa = 4.76)(CH_3-COOH)`
Presence of electron withdrawing group increases acidic strength of carboxylic acid.