Chemistry · May / June 2025 · Paper 12 · Question 18

Magnesium reacts with dilute sulfuric acid. Mg(s) + H2SO4(aq) → MgSO4(aq) + H2(g) Two experiments are carried out at 25 °C. experiment 1: 24.0 g of powdered magnesium is reacted with 100 cm³ of 1.0 mol/dm³ sulfuric acid. experiment 2: 24.0 g of powdered magnesium is reacted with 50 cm³ of 2.0 mol/dm³ sulfuric acid. During each experiment, the volume of hydrogen produced is measured at regular time intervals. The results are plotted on a graph. Which graph is correct?

1. AGraph A: dashed curve (experiment 2) rises faster and reaches the same final volume as the solid curve (experiment 1).
2. BGraph B: solid curve (experiment 1) rises faster and reaches the same final volume as the dashed curve (experiment 2).
3. CGraph C: solid curve (experiment 1) rises faster and reaches a higher final volume than the dashed curve (experiment 2).
4. DGraph D: solid curve (experiment 1) rises faster and reaches a higher final volume than the dashed curve (experiment 2).

As printed in the paper