Question

The pKₐ of a weak acid, HA, is 4.80. The pK???? of
a weak base, BOH, is 4.78. The pH of an aqueous
solution of the corresponding salt, BA, will be
(a) 9.58 (b) 4.79
(c) 9.22 (d) 7.01

Answer 1

The pH of an aqueous  solution of the corresponding salt, BA is (d) 7.01

Explanation:

From question, the weak acid and base be CH₃COONH₄

The salt hydrolysis formula is:

Kh = (Kw)/(Ka × Kb)

h = √((Kw)/(Ka × Kb))

pH = 1/2 [pKw + pKa - pKb]

Where,

pKw = 14 (constant)

pKa = 4.80 (given)

pKb = 4.78 (given)

On substituting the values, we get,

pH = 1/2 [14 + 4.80 - 4.78]

pH = 1/2 × 14.02

∴ pH = 7.01