Here's how to determine the net ionic equation for the reaction of chlorine gas with an aqueous solution of sodium iodide:

1. Write the balanced molecular equation:

Cl₂(g) + 2NaI(aq) → 2NaCl(aq) + I₂(s)

2. Write the complete ionic equation:

Cl₂(g) + 2Na⁺(aq) + 2I⁻(aq) → 2Na⁺(aq) + 2Cl⁻(aq) + I₂(s)

3. Identify the spectator ions:

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

4. Write the net ionic equation:

Cl₂(g) + 2I⁻(aq) → 2Cl⁻(aq) + I₂(s)

Explanation:

This reaction is a single displacement reaction where chlorine (Cl₂) is more reactive than iodine (I₂) and displaces it from the iodide ions. The net ionic equation shows the essential chemical change, which is the oxidation of iodide ions to iodine and the reduction of chlorine gas to chloride ions.