A student monitors the reaction between calcium carbonate chips and excess dilute hydrochloric acid using the apparatus shown below.
Which statement regarding this experiment is correct?
The cotton wool plug is used to prevent carbon dioxide gas from escaping, maintaining a constant mass reading on the balance.
The rate of mass loss decreases over time as the concentration of hydrogen ions in the acid decreases.
A plot of the balance reading against time yields a curve with a positive gradient that gradually decreases to zero.
The mass of the flask and its contents decreases by a larger amount in the final 30 seconds of the reaction than in the first 30 seconds.