Dissociation Constants for Acids (HSC SSCE Chemistry): Quizzes

The extent of ionisation in water

Water is the solvent; its conc. is constant

It ionises only to a small extent

Hydrofluoric acid ($7.6 \times 10^{-4}$)

[HA]equilibrium ≈ [HA]initial

Because [A⁻] = [H₃O⁺]

$\frac{[\text{A}^-]}{[\text{HA}]_{initial}} \times 100\%$

$K_{a1} > K_{a2} > K_{a3}$

Smaller p$K_a$ means stronger acid

Weak acid ($K_{a2} = 10^{-2}$)