Neco 2018 Chemistry Question 36

Consider the redox reaction that occurs in acidic solution where permanganate ion is reduced to manganese(II) ion and ferrous ion is oxidized to ferric ion. The half‑reaction for reduction is \(\ce{MnO4^- + 8H+ + 5e- -> Mn^{2+} + 4H2O}\) with \(E^\circ = +1.51\ \text{V}\). The half‑reaction for oxidation (as a reduction) is \(\ce{Fe^{3+} + e- -> Fe^{2+}}\) with \(E^\circ = +0.77\ \text{V}\). (a) Write the balanced overall redox equation. (b) Calculate the standard cell potential \(E^\circ_{\text{cell}}\) and state whether the reaction is spontaneous under standard conditions. (c) If 10.0 g of \(\ce{Fe^{2+}}\) are completely oxidised, determine the mass of \(\ce{KMnO4}\) required.