Chemistry · May / June 2021 · Paper 11 · Question 20

In which equations is the change in the underlined species correct? 1 CH4 + 2O2 → CO2 + 2H2O (oxidation) 2 2H2S + SO2 → 3S + 2H2O (reduction) 3 BrO3– + 5Br– + 6H+ → 3Br2 + 3H2O (reduction)

1. A1 only
2. B2 only
3. C1 and 3
4. D2 and 3

As printed in the paper