Here's why:

* Sodium sulfate is formed from the reaction of a strong acid (sulfuric acid, H₂SO₄) and a strong base (sodium hydroxide, NaOH).

* Strong acids and bases completely dissociate in water. This means that neither the sodium ions (Na⁺) nor the sulfate ions (SO₄²⁻) have any significant tendency to react with water to form H₃O⁺ (hydronium ions, which make a solution acidic) or OH⁻ (hydroxide ions, which make a solution basic).

Therefore, a solution of sodium sulfate will have a pH close to 7, indicating neutrality.