JAMB Chemistry 2019 Paper

Concept:A redox reaction involves simultaneous oxidation and reduction, identified by changes in oxidation states.Explanation:In $\mathrm{H}_2\mathrm{S}$, sulfur has oxidation state $-2$. It changes to $0$ in $\mathrm{S}$: oxidation occurs, so $\mathrm{H}_2\mathrm{S}$ is the reductant.In $\mathrm{SO}_2$, sulfur has oxidation state $+4$. It changes to $0$ in $\mathrm{S}$: reduction occurs, so $\mathrm{SO}_2$ is the oxidant.Therefore, this is a redox reaction where $\mathrm{SO}_2$ is the oxidant and $\mathrm{H}_2\mathrm{S}$ is the reductant.Answer:D. a redox reaction in which $\mathrm{SO}_2$ is the oxidant and $\mathrm{H}_2\mathrm{S}$ is the reductant