Chemistry · May / June 2022 · Paper 12 · Question 21

25 cm$^3$ of 1.0 mol / dm$^3$ hydrochloric acid reacts with 10 g of a solid to produce a gas. The solid is in excess. The graph labelled first experiment shows the volume of gas produced over time. Graphs P and Q show the volume of gas produced under different conditions. [graph] Which changes in conditions produce graphs P and Q, if all other conditions are kept the same?

1. AP uses a catalyst and Q has a lower temperature.
2. BP uses 25 cm$^3$ of more concentrated acid and Q uses smaller pieces of solid.
3. CP uses a higher temperature and Q uses 25 cm$^3$ of more dilute acid.
4. DP uses smaller pieces of solid and Q uses larger pieces of solid.

As printed in the paper