• # question_answer Consider the acidity of the carboxylic adds (i) $PhCOOH$ (ii) $o-N{{O}_{2}}{{C}_{6}}{{H}_{4}}COOH$ (iii) $p-N{{O}_{2}}{{C}_{6}}{{H}_{4}}COOH$ (iv) $mN{{O}_{2}}{{C}_{6}}{{H}_{4}}COOH$ Which of the following orders is correct? A)  (i) > (ii) > (iii) > (iv) B)  (ii) > (iv) > (iii) > (i) C)  (ii) > (iv) > (i) > (iii) D)  (ii) > (iii) > (iv) > (i)

(i) (ii) (iii) (iv) $-\text{N}{{\text{O}}_{\text{2}}}$group at any position shows electron withdrawing effect, thus acid strength is increased. But o-nitro benzoate ion is stabilised by intramolecular H-bonding like forces, hence its acid strength is maximum. Thus, the order of acid strength is (i) > (ii) > (iv) > (i).