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