Question

The increasing order of $ pK_{a} $ values for the following carboxylic acids is
(1) Acetic acid
(2) Formic acid
(3) Benzoic acid
(4) Trichloroacetic acid

• A. $ (4) <\, (2) <\, (3) < \,(1) $
• B. $ (3) < \,(1) <\, (2) <\, (4) $
• C. $ (2) <\, (4) <\, (3) <\, (1) $
• D. $ (3) < \,(1) <\, (4) <\, (2) $

Answer 1

Answer: (A)

The order of acidic strength is :
Trichloroacetic acid $>$ formic acid $>$ benzoic acid $>$ acetic acid
Hence, the increasing order of $pKa$ values is:
Trichloroacetic acid $<$ formic acid $<$ benzoic acid $<$ acetic acid