Here's how to write the net ionic equation for the reaction between sodium sulfate (Na₂SO₄) and barium chloride (BaCl₂):

1. Write the balanced molecular equation:

Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄(s) + 2NaCl(aq)

2. Write the complete ionic equation:

This involves breaking down all soluble ionic compounds into their respective ions:

2Na⁺(aq) + SO₄²⁻(aq) + Ba²⁺(aq) + 2Cl⁻(aq) → BaSO₄(s) + 2Na⁺(aq) + 2Cl⁻(aq)

3. Identify the spectator ions:

Spectator ions are those that appear on both sides of the equation and do not participate in the reaction. In this case, Na⁺ and Cl⁻ are spectator ions.

4. Write the net ionic equation:

This equation only includes the ions that directly react to form the precipitate:

Ba²⁺(aq) + SO₄²⁻(aq) → BaSO₄(s)

Therefore, the net ionic equation for the reaction of sodium sulfate and barium chloride is:

Ba²⁺(aq) + SO₄²⁻(aq) → BaSO₄(s)