Identify the correct net ionic equation for the reaction that occurs when solutions of HNO3 and KOH are mixed?
A. HNO3(aq) + KOH(aq) + H2O(l) + KNO3(s)
B. K+(aq) + NO3(aq) ? KNO3(aq)
C. H3O+(aq) + OH-(aq) ? 2H2O(l)
D. HNO3(aq) + KOH(aq) + H2O(l) + KNO3(aq) E. HNO3(aq) + OH-(aq) + H2O(l) + NO3-(aq)
The correct answer and explanation is :
The correct net ionic equation for the reaction that occurs when solutions of HNO3 and KOH are mixed is:
C. H₃O⁺(aq) + OH⁻(aq) → 2H₂O(l)
Explanation:
When HNO₃ (nitric acid) and KOH (potassium hydroxide) are mixed in water, they undergo a neutralization reaction. Let’s break down the process step by step:
- Dissociation of HNO₃: Nitric acid is a strong acid, meaning it dissociates completely in water. The dissociation equation is:
[ \text{HNO}_3 (aq) \rightarrow \text{H}^+ (aq) + \text{NO}_3^- (aq) ]
However, the hydrogen ion (H⁺) from this dissociation will quickly associate with water molecules to form hydronium ions (H₃O⁺), which is the actual form of H⁺ in aqueous solutions:
[ \text{H}^+ (aq) + \text{H}_2\text{O} (l) \rightarrow \text{H}_3\text{O}^+ (aq) ] - Dissociation of KOH: Potassium hydroxide is a strong base, so it also dissociates completely in water:
[ \text{KOH} (aq) \rightarrow \text{K}^+ (aq) + \text{OH}^- (aq) ] - Neutralization Reaction: The hydronium ion (H₃O⁺) from HNO₃ and the hydroxide ion (OH⁻) from KOH react to form water:
[ \text{H}_3\text{O}^+ (aq) + \text{OH}^- (aq) \rightarrow 2 \text{H}_2\text{O} (l) ]
This is the net ionic equation for the neutralization reaction, where the hydrogen ions from the acid neutralize the hydroxide ions from the base, forming water. - Spectator Ions: The potassium ions (K⁺) and nitrate ions (NO₃⁻) do not participate in the reaction and are considered spectator ions. They remain in solution and do not change during the reaction.
Now, let’s analyze the options:
- Option A: This is incorrect because it includes KNO₃ as a solid (KNO₃(s)), but KNO₃ is highly soluble in water, so it should be aqueous (KNO₃(aq)).
- Option B: This represents the dissociation of KNO₃, which is not relevant in the net ionic equation of the neutralization reaction.
- Option C: This is the correct net ionic equation for the neutralization reaction.
- Option D: This includes all species in their full forms and is not the net ionic equation because it includes spectator ions.
- Option E: This includes OH⁻ and HNO₃ as reactants, but it doesn’t correctly represent the complete neutralization.
Thus, C is the correct answer.