# During the electrolysis of dilute sulfuric acid using inert platinum electrodes, describe what is produced at each electrode and explain why the volume of gas collected at one electrode is greater than at the other.

> Cambridge International IGCSE Chemistry (0620) — 4.1 Electrolysis · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Hydrogen gas is produced at the cathode (negative electrode)
2. Oxygen gas is produced at the anode (positive electrode)
3. The volume of hydrogen is greater / twice the volume of oxygen
4. Because water molecules / hydrogen ions and oxide/hydroxide ions split in a 2:1 ratio, so twice as many hydrogen molecules are formed for every oxygen molecule / water splits as H₂O giving two H for every one O

## Key terms

- [electrolysis](https://www.gradenine.co.uk/glossary/electrolysis)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/during-the-electrolysis-of-dilute-sulfuric-e68e5922) · Published by Druglandscape Ltd.