Consider the acidity of the carboxylic acids : (i) C6H5COOH (ii) o–NO2C6H4COOH (iii) p–NO2C6H4COOH (iv) m–NO2C6H4COOH Which of the following order is correct ?

Electron-withdrawing group increases the acidity of the carboxylic acid. And we know that the ortho isomer of the benzoic acid given will be more acidic than the other two meta and para isomers due to ortho effect. And the -NO2 group is electron Carboxylic Acid and Its Derivatives 12 withdrawing group it stabilise the carboxylate ion by -M effect. Thus the order of acidity is given as- Thus, the correct option is (d)