(Originais Teachy 2023) - Question Medium of Chemistry

Potassium permanganate, KMnO4, is a reagent widely used in analytical chemistry to determine the concentration of reducing agents. In a titration, a solution of KMnO4 of known concentration reacts with a reducing agent under acidic conditions, where permanganate is reduced to manganese(II) ions and MnO4- ions are converted to Mn2+. Consider the following equilibrium that occurs during the titration, with a reducing agent that converts permanganate to Mn2+: 8 H+ + MnO4- + 5 e- -> Mn2+ + 4 H2O. If in a practical experiment, 0.025 mol of KMnO4 reacts completely with a reducing agent, determine: (i) The number of moles of electrons transferred during the reaction. (ii) The oxidation number of manganese in MnO4- and in Mn2+ after the reaction.