Question

Calculate the pH of a solution containing a salt AcNa derived from a strong base (NaOH) and a weak acid (AcH), like CH₃COONa, KF, NaNO₂ and so on. In this case two processes have to be considered:

1. Dissociation of the salt, within the assumption that the salt is a strong electrolyte:

AcNa → Ac^- + Na⁺,   for instance: CH₃COONa → CH₃COO^- + Na⁺

2. the hydrolysis of the water

Ac^- + H₂O ⇌ AcH + OH^-,    for example: CH₃COO^- + H₂O ⇌ CH₃COOH + OH^-

knowing that the initial concentration of the salt is 1.7 M and the acid dissociation constant, K_a , is 2.23e-10.

pH=?

Answer 1

I 1 17n 7H -2 1.7M Ko- lo 2.23 f16'。 PH- 14-poh, 11-94 Ka = 4.48x105