Sodium sulfate (Na₂SO₄) is a neutral salt. This means that its solution in water will have a pH value of approximately 7.

Here's why:

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

* Strong acids and strong bases completely dissociate in water, producing ions. In the case of sodium sulfate, the ions produced are sodium (Na⁺) and sulfate (SO₄²⁻).

* Neither sodium nor sulfate ions have a significant tendency to react with water to form H⁺ or OH⁻ ions. This means they don't contribute to the acidity or basicity of the solution.

Therefore, a solution of sodium sulfate will have a neutral pH, similar to pure water.