Question

When a solution of benzoic acid was titrated with naoh the ph of the solution when half the acid neutralized was 4.2. dissociation constant of the acid is?

Answer 1

When a solution of benzoic acid was titrated with sodium hydroxide the pH of the solution when half the acid neutralized was 4.2.

dissociation constant of the acid can be calculated when we first put down all that we require first.

pH = 4.2

the equilibrium concentration, C = 10^-4.2

                                                  = 6.3 x 10^-5 M

but dissociation ka = C∝²

ka of benzoic acid 6.4 x 10^-5.