AIIMS 2019 Chemistry Acidity of Organic Compounds MCQ Question
"-I" effect of chlorine makes p-chlorobenzoic acid more acidic because, the presence of electron withdrawing groups on the phenyl ring increases their acidity in comparison to unsubstituted acids.
Chlorine is highly electronegative
Chlorine donates electrons
Chlorine withdraws electrons
Chlorine is a good leaving group
Correct Answer
Detailed Explanation
The "-I" (inductive) effect of chlorine refers to its ability to withdraw electrons from the phenyl ring due to its high electronegativity, which stabilizes the negative charge on the carboxylate ion (−COO⁻) formed upon deprotonation of p-chlorobenzoic acid. This increased stability enhances the acidity of the acid compared to unsubstituted benzoic acid. Option A is misleading because, while chlorine is electronegative, it does not directly explain the increased acidity; option B is incorrect as chlorine does not donate electrons; and option D is irrelevant in this context, as the leaving group ability does not influence the acidity of the acid itself.
Found an issue with this question?