Questions: Use H+ for hydronium ion. Write a net ionic equation for the reaction that occurs when potassium sulfide and excess hydroiodic acid are combined.

Use H+ for hydronium ion.

Write a net ionic equation for the reaction that occurs when potassium sulfide and excess hydroiodic acid are combined.

Transcript text: Use $\mathrm{H}^{+}$for hydronium ion. Write a net ionic equation for the reaction that occurs when potassium sulfide and excess hydroiodic acid are combined.

Solution

Solution Steps

Step 1: Write the balanced molecular equation

The reaction between potassium sulfide (K₂S) and hydroiodic acid (HI) produces hydrogen sulfide (H₂S) gas and potassium iodide (KI). The balanced molecular equation is:

K₂S(aq) + 2HI(aq) → H₂S(g) + 2KI(aq)

Step 2: Write the complete ionic equation

In the complete ionic equation, soluble ionic compounds are written as separate ions.

2K⁺(aq) + S²⁻(aq) + 2H⁺(aq) + 2I⁻(aq) → H₂S(g) + 2K⁺(aq) + 2I⁻(aq)

Step 3: Write the net ionic equation

The potassium (K⁺) and iodide (I⁻) ions appear on both sides of the equation and are therefore spectator ions. Remove the spectator ions to get the net ionic equation.

S²⁻(aq) + 2H⁺(aq) → H₂S(g)