question_answer

The carboxylic acid of least strength among the following is

A)  p-nitrobenzoic acid

B)  p-methylbenzoic acid

C)  p-chlprobenzoic acid

D)  p-methoxybenzoic acid

Correct Answer: D

Solution :

 Higher the tendency of an acid to release a proton, higher is the acidic strength. Presence of electron releasing group   such as\[-OC{{H}_{3}},C{{H}_{3}}\]etc (\[-OC{{H}_{3}}\] is more electron releasing than \[C{{H}_{3}}\]group) increases the electron density of the carboxylate anion. Consequently, the anion becomes unstable and the release of proton becomes difficult. Thus, weaker is the acid. Hence, \[p-\]methoxy benzoic acid                            is the least acidic among the given acids.