Question
If a few drops of HCl is added to the buffer solution with the following equilibrium, ________.
NH4+(aq) + H2O(1) ⇐ H3O+(aq) + NH3(aq)
the concentrations of both NH3 and NH4+ decrease
the concentration of NH3 decreases but NH4+ increases
the concentration of NH3 increases but NH4+ decreases
the concentrations of both NH3 and NH4+ increase
NH4+(aq) + H2O(1) ⇐ H3O+(aq) + NH3(aq)
the concentrations of both NH3 and NH4+ decrease
the concentration of NH3 decreases but NH4+ increases
the concentration of NH3 increases but NH4+ decreases
the concentrations of both NH3 and NH4+ increase
Answers
GPT-4o mini
When a few drops of HCl, a strong acid, are added to the buffer solution containing the equilibrium:
\[ \text{NH}_4^+(aq) + \text{H}_2\text{O}(l) \leftrightarrow \text{H}_3\text{O}^+(aq) + \text{NH}_3(aq) \]
the added HCl will increase the concentration of hydronium ions (\( \text{H}_3\text{O}^+ \)) in the solution. According to Le Chatelier's principle, the equilibrium will shift to the left in order to counteract the increase in \( \text{H}_3\text{O}^+ \).
As the equilibrium shifts to the left:
- \( \text{NH}_4^+ \) (ammonium) will increase because it is being produced from \( \text{NH}_3 \) and \( \text{H}_3\text{O}^+ \).
- \( \text{NH}_3 \) (ammonia) will decrease as it is consumed to form more \( \text{NH}_4^+ \).
Therefore, the correct answer is:
**the concentration of NH3 increases but NH4+ decreases.**
\[ \text{NH}_4^+(aq) + \text{H}_2\text{O}(l) \leftrightarrow \text{H}_3\text{O}^+(aq) + \text{NH}_3(aq) \]
the added HCl will increase the concentration of hydronium ions (\( \text{H}_3\text{O}^+ \)) in the solution. According to Le Chatelier's principle, the equilibrium will shift to the left in order to counteract the increase in \( \text{H}_3\text{O}^+ \).
As the equilibrium shifts to the left:
- \( \text{NH}_4^+ \) (ammonium) will increase because it is being produced from \( \text{NH}_3 \) and \( \text{H}_3\text{O}^+ \).
- \( \text{NH}_3 \) (ammonia) will decrease as it is consumed to form more \( \text{NH}_4^+ \).
Therefore, the correct answer is:
**the concentration of NH3 increases but NH4+ decreases.**