What happens when H+ is added to ammonium hydroxide and ammonium chloride buffer?
Correct answer: C. Reaction will move forward
- A. More ammonium hydroxide is formed
- B. Reaction will move reverse
- C. Reaction will move forward
- D. No effect on equilibrium
Explanation
The added hydrogen ions are mopped up by the weak base ammonium hydroxide, which reacts forward to give ammonium ions and water, so the pH barely shifts. This is exactly what buffering means: the reservoir of base neutralises added acid. If alkali were added instead, the ammonium ions from the salt would supply protons to neutralise it.
This question appeared on the UHS MDCAT 2025 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Buffer Solutions
Buffer solutions resist changes in pH when small amounts of acid or base are added, using a weak acid and its conjugate base or a weak base and its conjugate acid. Work includes buffer action, the common-ion effect, Henderson-Hasselbalch calculations, buffer capacity, and the difference between acidic and basic buffers.
Practise Chemical Equilibrium
625 free Chemical Equilibrium MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.