(a)[1]
State an equation for the reaction that takes place.
(b(i))[4]
Explain why the copper(II) sulfate solution has a colour.
(b(ii))[1]
Suggest a reason why the copper(I) iodide precipitate is white.
(c)[2]
Use suitable $E^{\circ}$ values from the Data Booklet to decide whether iodide ions are able to reduce $\text{Cu}^{2+}$ to $\text{Cu}^+$ under standard conditions. Justify your answer.
(d)[2]
An excess of sodium iodide is added to copper(II) sulfate solution. Copper(I) iodide appears as a precipitate. After the precipitate forms, $[\text{Cu}^+]$ is much lower than $1.0\ \text{mol dm}^{-3}$. Use this and your answer to (c) to explain how the relevant electrode potentials change and therefore why $\text{I}^-$ ions can reduce $\text{Cu}^{2+}$ ions.