CHEMICAL ANTAGONISM OF IONS : II. ANTAGONISM BETWEEN ANIONS AND ALSO BETWEEN CATIONS AND ANIONS IN THEIR EFFECT ON OXALATE ACTIVITY.

Sulfate ions (SO₄⁼) produce an anomalous effect on the ionization of oxalate diion, opposite in direction to the effect of Mg⁺⁺ ions. This effect of sulfate is antagonized by the presence of Cl^- ions according to the equation:

See PDF for Equation

where f' is the antilog of the increase in pK₂' due to the sulfate.

In solutions containing up to 0.03 molar MgSO₄ the effect of Mg⁺⁺ predominates over that of SO₄⁼. Above 0.1 molar the effect of SO₄⁼ predominates and tends to neutralize the initial deviation.

In solutions containing fixed amounts of MgCl₂ and varying amounts of NaSO₄ (or vice versa) the effects of these two salts sharply antagonize each other in all proportions.