Alyssum plants are grown on mine waste containing nickel compounds. After the plants are burned, their ash is dissolved in acid to make a solution containing nickel ions. Nickel is recovered from separate samples of this solution by electrolysis and by displacement with a metal more reactive than nickel.
Which statement is correct?
Nickel ions are reduced by gaining electrons in both methods; during displacement, the more reactive metal is oxidised by losing electrons.
Nickel ions are reduced by gaining electrons during electrolysis but are oxidised during displacement; the more reactive metal also loses electrons.
Nickel ions are oxidised by losing electrons during electrolysis but are reduced during displacement; the more reactive metal also gains electrons.
Nickel ions are oxidised by losing electrons in both methods; during displacement, the more reactive metal is reduced by gaining electrons.
136 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.