Acid ionisation constant Ka (Ka = [H+][A-]/[HA] for HA ⇌ H+ + A-)

jee-mainjee-advancedneet-ug

Ka = [H+][A-]/[HA] for HA ⇌ H+ + A-

What each symbol means

SymbolWhat it stands for
K_aStrength measure of weak acid (larger = stronger)
[HA]Equilibrium concentration of undissociated acid

When to use this

Dilute aqueous weak acid; activity ≈ concentration; ICE tables common.