An underwater research team tests simple cells for a sampling tag. In each cell, the two electrodes are dipped in the same electrolyte and the tests are carried out under the same conditions. The metals are listed in decreasing reactivity: magnesium, zinc, iron, copper.
Which electrode pair is expected to produce the smallest voltage, and why?
Zinc and copper, because copper is the least reactive of the four metals
Magnesium and copper, because these metals are the furthest apart in reactivity
Zinc and iron, because these metals are the closest together in reactivity
Magnesium and iron, because it is the only pair without a copper electrode
90 exam-style questions on AQA GCSE Chemistry 5.2 Chemical cells and fuel cells, covering 5.2.1 Cells and batteries, 5.2.2a Fuel cells, and 5.2.2b Half equations for hydrogen fuel cells. Each one has a worked solution and a mark scheme showing where the marks go.