About Rates of reaction and equilibrium in O Level Chemistry
Rates of reaction and equilibrium is one of the 12 main topics in our O Level Chemistry (Cambridge (CAIE) 5070) question bank, and about 7% of its real questions come from it. Tayyari Karo has 46 real questions on this topic from 2021 to 2026, from Paper 1, Paper 2, Paper 4; 29 are multiple choice and marked instantly, and the rest are structured questions with a model answer. By difficulty: 39 medium, 4 easy, 3 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
Try 6 real questions
These are real past-paper questions. Think of your answer first, then open the explanation.
May/June 2026 · Paper 1 · Rates of reaction and equilibrium
When bismuth(III) chloride, BiCl3, is added to water, a reaction occurs and a white precipitate of BiOCl is formed: BiCl3(aq) + H2O(l) ⇌ BiOCl(s) + 2HCl(aq).
Which changes increase the mass of white precipitate formed?
1 adding more water
2 adding aqueous sodium hydroxide
3 adding dilute hydrochloric acid
- 1 and 2
- 1 and 3
- 1 only
- 2 and 3
Show answer and explanation
Answer: A. 1 and 2
More water pushes the equilibrium right. Sodium hydroxide neutralises the HCl, removing a product and also pushing the equilibrium right. Adding HCl pushes it left.
May/June 2025 · Paper 1 · Rates of reaction and equilibrium
In 2SO2 + O2 <=> 2SO3, add O2 gives
- left
- right
- no change
- stops
Show answer and explanation
Answer: B. right
Right (more reactant).
Oct/Nov 2024 · Paper 1 · Rates of reaction and equilibrium
Catalyst
- increases yield
- lowers activation energy
- shifts equilibrium
- is consumed
Show answer and explanation
Answer: B. lowers activation energy
Lowers activation energy.
Oct/Nov 2023 · Paper 1 · Rates of reaction and equilibrium
Catalyst not consumed means
- it is used up
- it is regenerated
- yield increases
- equilibrium shifts
Show answer and explanation
Answer: B. it is regenerated
Catalyst regenerated.
Oct/Nov 2022 · Paper 1 · Rates of reaction and equilibrium
Powdered CaCO₃ reacts faster than chips because
- lower temperature
- greater surface area
- less mass
- higher activation energy
Show answer and explanation
Answer: B. greater surface area
More surface area.
May/June 2021 · Paper 1 · Rates of reaction and equilibrium
Haber: N₂ + 3H₂ ⇌ 2NH₃. Which row correct?
- pressure up moves left
- pressure down no change
- catalyst moves right
- catalyst no change
Show answer and explanation
Answer: D. catalyst no change
Catalyst does not shift equilibrium.
