The reaction $\mathrm{Zn}(s) + \mathrm{CuSO}_4(aq) \rightarrow \mathrm{ZnSO}_4(aq) + \mathrm{Cu}(s)$ is best classified as which type of redox reaction?

1. syllabus names four types of redox reactions: combination, decomposition, displacement and disproportionation. 2. In a DISPLACEMENT reaction, one element displaces another from a compound. Here Zn (above Cu in the reactivity series) displaces Cu from $\mathrm{CuSO}_4$. 3. Verify electron transfer: Zn ($0 \rightarrow +2$) is oxidised; $\mathrm{Cu}^{2+}$ ($+2 \rightarrow 0$) is reduced. 4. It is not a combination (two reactants → one product needed) or a decomposition (one reactant → many). Disproportionation requires the SAME element to be both oxidised and reduced — here Zn and Cu are different elements so the change is not symmetric in a single element. _Source: syllabus Chemistry Part 2, Ch 7, §7.2.1 "Competitive Electron Transfer" + §7.3.1 "Displacement Reactions", p. 3 + p. 8._