question_answer

Consider the acidity of the carboxylic acids                 \[PhCOOH\]       \[o-N{{O}_{2}}{{C}_{6}}{{H}_{4}}COOH\]               \[p-N{{O}_{2}}{{C}_{6}}{{H}_{4}}COOH\]               \[m-N{{O}_{2}}{{C}_{6}}{{H}_{4}}COOH\] Which of the following order is correct?                [AIEEE 2004]

A)                 \[b>d>a>c\]      

B)                 \[b>d>c>a\]

C)                 \[a>b>c>d\]      

D)                 \[b>c>d>a\]

Correct Answer: D

Solution :

                                                                                                                                  Electron withdrawing group, increases the acidity of benzoic acid, O-isomer will have higher acidity then corresponding m and p-isomer due to ortho effect.