# Explain why a cell made from a magnesium half-cell and a silver half-cell produces a greater voltage than a cell made from a magnesium half-cell and a nickel half-cell, and state which electrode acts as the negative electrode in the magnesium–silver cell.

> AQA A-Level Chemistry (7405) — 3.1.11 Electrode potentials and electrochemical cells (A-Level only) · Explain · 5 marks

> Standard electrode potentials (E°) relative to the standard hydrogen electrode: Mg²⁺/Mg = −2.37 V; Ni²⁺/Ni = −0.25 V; Ag⁺/Ag = +0.80 V.

## Mark scheme (5 marks)

1. The cell voltage depends on the difference between the two standard electrode potentials
2. Magnesium–silver cell has a larger difference in electrode potentials than magnesium–nickel cell
3. Silver has a more positive/higher standard electrode potential than nickel
4. Magnesium has the more negative/lower standard electrode potential so it acts as the negative electrode
5. Magnesium is oxidised / loses electrons / is the anode, so it is the negative electrode

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-a-cell-made-from-aabf3e84) · Published by Druglandscape Ltd.