Sulfuryl chloride decomposes in a reversible reaction.
SO2Cl2(g)⇌SO2(g)+Cl2(g) \text{SO}_2\text{Cl}_2\text{(g)} \rightleftharpoons \text{SO}_2\text{(g)} + \text{Cl}_2\text{(g)} SO2Cl2(g)⇌SO2(g)+Cl2(g)The reaction is at dynamic equilibrium in a sealed container at constant temperature. Some sulfur dioxide is added. The table shows the rates of the forward and reverse reactions.
| Reading | Rate of forward reaction (arbitrary units) | Rate of reverse reaction (arbitrary units) |
|---|---|---|
| Before sulfur dioxide is added | 3.2 | 3.2 |
| Immediately after sulfur dioxide is added | 3.2 | 5.4 |
| 30 s after sulfur dioxide is added | 3.6 | 4.6 |
| 60 s after sulfur dioxide is added | 4.1 | 4.1 |
| 90 s after sulfur dioxide is added | 4.1 | 4.1 |
Explain how the amount of sulfuryl chloride changes after sulfur dioxide is added and when the data first show that a new dynamic equilibrium has been reached.
A catalyst is added at 90 s. Explain how this affects the rates of the reactions and the amount of sulfuryl chloride in the equilibrium mixture.
124 exam-style questions on OCR GCSE Chemistry 5.3 Equilibria, covering 5.3.1 Reversible reactions and dynamic equilibrium and 5.3.2 Changing the position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.