An aqueous solution of sodium sulfate, Na2SO4(aq)\text{Na}_2\text{SO}_4\text{(aq)}Na2SO4(aq), is electrolysed using inert platinum electrodes. A few drops of universal indicator are added to the solution, which is initially green (pH=7\text{pH} = 7pH=7).
Which statement correctly describes the products formed and the colour changes observed around the electrodes during this electrolytic process?
Oxygen gas is produced at the anode, causing the surrounding solution to turn red (pH<7\text{pH} < 7pH<7), while hydrogen gas is produced at the cathode, causing the surrounding solution to turn purple (pH>7\text{pH} > 7pH>7).
Sodium metal is deposited on the cathode, causing the surrounding solution to turn purple (pH>7\text{pH} > 7pH>7), while oxygen gas is produced at the anode, causing the surrounding solution to turn red (pH<7\text{pH} < 7pH<7).
Hydrogen gas is produced at the cathode, causing the surrounding solution to turn red (pH<7\text{pH} < 7pH<7), while oxygen gas is produced at the anode, causing the surrounding solution to turn purple (pH>7\text{pH} > 7pH>7).
Oxygen gas is produced at the cathode, causing the surrounding solution to remain green (pH=7\text{pH} = 7pH=7), while hydrogen gas is produced at the anode, causing the surrounding solution to remain green (pH=7\text{pH} = 7pH=7).
Electrolytic processes Questions
Practise Edexcel GCSE Chemistry Electrolytic processes with exam-style questions for Foundation and Higher tier. 100 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.