If to an ionic equilibrium, AB A+ + B‾ , a salt containing a common ion is added, the equilibrium shifts in the backward direction. This is called common Ion effect. Acetic acid being a weak acid, ionizes to a small extent as: CH3COOH CH3COO‾ + H+ To this solution , suppose the salt of this weak acid with a strong base is added. It ionizes almost completely in … [Read more...] about Common Ion Effect