What is the net ionic equation for the reaction: HNO3(aq) + K2S(aq) → H2S(g) + KNO3(aq)?

• A. 2NO3^-(aq) + 2K^+(aq) → 2KNO3(aq)
• B. 2H^+(aq) + S^{2-}(aq) → H2S(g)
• C. 2H^+(aq) + 2NO3^-(aq) + 2K^+(aq) + S^{2-}(aq) → H2S(g) + 2K^+(aq) + 2NO3^-(aq)
• D. HNO3(aq) + K2S(aq) → H2S(g) + KNO3(aq)

Answer: (B)

Verified step by step guidance

1. Write the balanced molecular equation for the reaction: \(\mathrm{HNO_3 (aq) + K_2S (aq) \rightarrow H_2S (g) + 2 KNO_3 (aq)}\).
2. Dissociate all strong electrolytes (soluble ionic compounds and strong acids) into their ions: \(\mathrm{HNO_3 \rightarrow H^+ + NO_3^-}\) and \(\mathrm{K_2S \rightarrow 2 K^+ + S^{2-}}\). Note that \(\mathrm{H_2S}\) is a gas and does not dissociate.
3. Write the full ionic equation by substituting the dissociated ions: \(\mathrm{H^+ (aq) + NO_3^- (aq) + 2 K^+ (aq) + S^{2-} (aq) \rightarrow H_2S (g) + 2 K^+ (aq) + 2 NO_3^- (aq)}\).
4. Identify the spectator ions, which are ions that appear unchanged on both sides of the equation. Here, \(\mathrm{K^+}\) and \(\mathrm{NO_3^-}\) are spectator ions.
5. Remove the spectator ions to write the net ionic equation: \(\mathrm{2 H^+ (aq) + S^{2-} (aq) \rightarrow H_2S (g)}\).