Which ions are spectator ions in the reaction between KOH(aq) and HNO3(aq)?

• A. K^+ and NO_3^-
• B. H^+ and OH^-
• C. K^+ and OH^-
• D. H^+ and NO_3^-

Answer: (A)

Verified step by step guidance

1. Write the balanced molecular equation for the reaction between potassium hydroxide (KOH) and nitric acid (HNO_3): \[\mathrm{KOH (aq) + HNO_3 (aq) \rightarrow KNO_3 (aq) + H_2O (l)}\]
2. Write the complete ionic equation by dissociating all strong electrolytes into their ions: \[\mathrm{K^+ (aq) + OH^- (aq) + H^+ (aq) + NO_3^- (aq) \rightarrow K^+ (aq) + NO_3^- (aq) + H_2O (l)}\]
3. Identify the ions that appear unchanged on both sides of the ionic equation. These ions do not participate in the formation of the product and are called spectator ions.
4. From the ionic equation, observe that \[\mathrm{K^+}\] and \[\mathrm{NO_3^-}\] ions are present on both sides without change, so they are the spectator ions.
5. The ions \[\mathrm{H^+}\] and \[\mathrm{OH^-}\] combine to form water, so they are the ions involved in the reaction, not spectators.