In experiment 1, excess marble chips (calcium carbonate) were added to \(50.0\ \text{cm}^3\) of \(1.00\ \text{mol dm}^{-3}\) hydrochloric acid at \(25^\circ\text{C}\), and the total volume of carbon dioxide was recorded. The result is the black dashed curve. Curves P, Q, R and S were obtained in other experiments in which one or two conditions were changed. \[ \mathrm{CaCO_3(s) + 2HCl(aq) \rightarrow CaCl_2(aq) + H_2O(l) + CO_2(g)} \]


Experiment 2 used \(25.0\ \text{cm}^3\) of \(2.00\ \text{mol dm}^{-3}\) HCl, and experiment 3 used \(50.0\ \text{cm}^3\) of \(0.500\ \text{mol dm}^{-3}\) HCl. All other conditions were the same as in experiment 1 (excess marble chips of the same size, \(25^\circ\text{C}\)). Which curves represent experiments 2 and 3?