Chemistry · Oct / Nov 2025 · Paper 12 · Question 11

The apparatus shown is used to investigate the electrolysis using inert electrodes of dilute sulfuric acid and concentrated aqueous sodium chloride in separate experiments. [diagram of electrolysis apparatus with test-tube X, test-tube Y, positive electrode, negative electrode] Which row shows the ratio of volume of gas collected in each test-tube?

1. Aratio of volume of gas in X and Y with dilute H2SO4 X : Y = 1 : 2; ratio of volume of gas in X and Y with concentrated aqueous NaCl X : Y = 2 : 1
2. Bratio of volume of gas in X and Y with dilute H2SO4 X : Y = 1 : 1; ratio of volume of gas in X and Y with concentrated aqueous NaCl X : Y = 1 : 1
3. Cratio of volume of gas in X and Y with dilute H2SO4 X : Y = 1 : 2; ratio of volume of gas in X and Y with concentrated aqueous NaCl X : Y = 1 : 1
4. Dratio of volume of gas in X and Y with dilute H2SO4 X : Y = 2 : 1; ratio of volume of gas in X and Y with concentrated aqueous NaCl X : Y = 1 : 2

As printed in the paper