Electrodes

[Sarah Zhao 4C]

In a Cu/Zn galvanic cell, why can we use Cu as an electrode but must use Pt as the other?

[David S]

I don't believe we need to use Platinum as an electrode here because the copper and zinc can react with their solid electrodes to be reduced and oxidized respectively, making both metals decent conductors of electricity. We would need an inert Platinum electrode to act as an electricity conductor if the oxidation or reduction reactions involve species that are poor conductors of electricity. For example, the galvanic cell Mg(s) │ Mg2+(aq) ║ H+(aq) │ H2(g) │ Pt(s) uses platinum electrode to conduct electricity in the H+ solution because H+ is a poor conductor of electricity.

[ryanhon2H]

An inert conductor is used if there is no metal electrode. In this case copper is metal and an electrode, so an inert conductor would not be needed.