Task

Excess concentrated hydrochloric acid acted on 15.8 g of potassium permanganate. The chlorine evolved was split into two equal parts. The first was passed through hot (excess) potassium hydroxide solution; the oxygen-containing salt formed was isolated and heated with MnO₂. The second part reacted with excess heated iron. 1) Balance the KMnO₄ + HCl reaction by electron balance; find the chlorine volume (L, STP), the amount of HCl consumed and what part of it acted as the reducing agent. 2) Write the reaction of chlorine with hot alkali (disproportionation) and calculate the mass of the oxygen-containing salt. 3) Write the decomposition of this salt with MnO₂ and find the volume of oxygen evolved (L, STP). 4) Write the reaction of chlorine with iron, calculate the product mass and explain why iron(II) chloride is not formed. For every part, show the method (reaction equations, formulas, reasoning) and all calculations step by step.