Question

The ionisation constant of an acid, $K_a$ is the measure of strength of an acid. The $K_a$ values of acetic acid, hypochlorous acid and formic acid are 1.74 × 10⁻⁵, 3.0 × 10⁻⁸ and 1.8 × 10⁻⁴ respectively. Which of the following orders of pH of 0.1 mol dm⁻³ solutions of these acids is correct?
(a) Acetic acid > hypochlorous acid > formic acid
(b) Hypochlorous acid > acetic acid > formic acid
(c) Formic acid > hypochlorous acid > acetic acid
(d) Formic acid > acetic acid > hypochlorous acid

Answer 1

option (b) is correct