The acid-base neutralization reaction of a weak acid with a strong base is shown below: HNO3(aq) + CsOH(aq) → CsNO3(aq) + H2O(l) Write the net ionic equation: H+(aq) + OH-(aq) → H2O(l) List the spectator ions: Cs+(aq) and NO3-(aq
The Correct Answer and Explanation is:
Net Ionic Equation:
H+(aq)+OH−(aq)→H2O(l)\text{H}^+(aq) + \text{OH}^-(aq) \rightarrow \text{H}_2\text{O}(l)H+(aq)+OH−(aq)→H2O(l)
Spectator Ions:
Cs+(aq) and NO3−(aq)\text{Cs}^+(aq) \text{ and } \text{NO}_3^-(aq)Cs+(aq) and NO3−(aq)
Explanation
In the reaction:HNO3(aq)+CsOH(aq)→CsNO3(aq)+H2O(l)\text{HNO}_3(aq) + \text{CsOH}(aq) \rightarrow \text{CsNO}_3(aq) + \text{H}_2\text{O}(l)HNO3(aq)+CsOH(aq)→CsNO3(aq)+H2O(l)
we are observing a typical acid-base neutralization. Cesium hydroxide (CsOH) is a strong base, and nitric acid (HNO₃), contrary to the original claim, is actually a strong acid, not a weak one. Both HNO₃ and CsOH completely dissociate in aqueous solution.
Upon dissociation:
- HNO₃ → H⁺ + NO₃⁻
- CsOH → Cs⁺ + OH⁻
When mixed in solution, the H⁺ ions from the acid and the OH⁻ ions from the base react to form water, a neutral and stable compound. This formation of water is the essence of the net ionic equation, which includes only the species directly involved in the chemical change.
Thus, the net ionic equation is:H+(aq)+OH−(aq)→H2O(l)\text{H}^+(aq) + \text{OH}^-(aq) \rightarrow \text{H}_2\text{O}(l)H+(aq)+OH−(aq)→H2O(l)
The other ions, Cs⁺ and NO₃⁻, do not participate in the reaction itself. They remain unchanged in solution and are therefore called spectator ions. Spectator ions help maintain charge balance in the solution but are not directly involved in the formation of products. When writing net ionic equations, these ions are excluded to focus on the actual chemical change.
To summarize: the neutralization of HNO₃ with CsOH results in the formation of water, with Cs⁺ and NO₃⁻ acting as spectator ions. This is a clear example of how strong acid-strong base reactions simplify to a basic proton (H⁺) and hydroxide (OH⁻) interaction forming water.
