Chemistry · Oct / Nov 2021 · Paper 12 · Question 19

The apparatus shows a method of following the rate of the reaction between magnesium carbonate, MgCO3, and dilute nitric acid, HNO3. MgCO3(s) + 2HNO3(aq) → Mg(NO3)2(aq) + H2O(l) + CO2(g) The graph shows the volume of gas collected against time. Three statements are made about the experiment. 1 The mass of the flask and its contents decreases as time increases. 2 The rate of the reaction decreases as time increases. 3 The reaction has finished after four minutes. Which statements are correct?

1. A1, 2 and 3
2. B1 and 2 only
3. C1 and 3 only
4. D2 and 3 only

As printed in the paper