Chemistry · May / June 2023 · Paper 12 · Question 9

Aqueous hydrogen peroxide, H2O2, decomposes slowly at 25 °C. 2H2O2(aq) → 2H2O(l) + O2(g) The decomposition reaction takes place faster when a catalyst is added. A student adds a small amount of catalyst to 10 cm3 of 1.0 mol/dm3 H2O2(aq) and collects the gas formed. The volume of gas collected is 90 cm3. All measurements are at room temperature and pressure. What is the percentage yield of O2(g)?

1. A28.1%
2. B37.5%
3. C56.3%
4. D75.0%

As printed in the paper