• # question_answer Benzoic acid is a monobasic acid. When 1.22 g of its pure sample are dissolved in water and titrated against base, 50 ml of 0.2 M NaOH are used up. Calculate the molar mass of benzoic acid.

1000 ml of 1 M NaOH will neutralize acid $=\frac{1.22}{50\times 0.2}\times 1000=122\,g$ But 1000 ml of 1 M NaOH contain 1 mole of NaOH and will neutralize 1 mole of monobasic acid. Hence, molar mass of benzoic acid $=122\,g\,\text{mo}{{\text{l}}^{-1}}$.