A student connects two graphite electrodes to a direct current supply and places them in solid zinc bromide. The student measures the current, then heats the zinc bromide until it melts and measures the current again. After the molten zinc bromide cools and solidifies, the current is measured once more.
| State of zinc bromide | Current |
|---|---|
| Solid | 0.00 A |
| Molten | 0.42 A |
| Solid after cooling | 0.00 A |
Explain the pattern in the current readings and predict the substances formed at each electrode while the zinc bromide is molten.
98 exam-style questions on OCR GCSE Chemistry 3.4 Electrolysis, covering 3.4.1 Products formed at the electrodes in electrolysis and 3.4.2 The technique of electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.