A chemical company investigates two methods for electrolysing the binary ionic compound zinc iodide, ZnI2\text{ZnI}_2ZnI2, using inert electrodes.
Method P: zinc iodide is melted and then electrolysed.
Method Q: zinc iodide is dissolved in water and then electrolysed.
Name the product at each electrode in method P. Explain how each product forms.
Name the product at the cathode in method Q. Explain why this product is different from the cathode product in method P.
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.