2023 · Q11
Consider the following redox reaction:
2Cu₂O (s) + Cu₂S (s) ⟶ 6Cu (s) + SO₂ (g)
Identify the species among the following acting as oxidant and reductant, respectively:
general-sciencechemistry
- ACu(I) and S of Cu₂S
- BCu and S of SO₂
- CCu and O of SO₂
- DCu(I) and O of SO₂
Explanation
In the reaction 2Cu2O + Cu2S gives 6Cu + SO2, copper in Cu2O is in the +1 oxidation state and is reduced to Cu(0), gaining electrons, so Cu(I) acts as the oxidant. Sulphur in Cu2S is in the -2 state and is oxidised to +4 in SO2, losing electrons, so the sulphur of Cu2S acts as the reductant. The oxygen atoms do not change oxidation state in a way that defines the redox roles here. Hence the oxidant and reductant are Cu(I) and S of Cu2S respectively.