To measure the quantity of MnCl dissolved in an aqueous solution, it was completely converted to KMnO4 using the reaction, MnCl + KS2O8 + HO KMnO4 + HSO4 + HCl (equation not balanced). Few drops of concentrated HCl were added to this solution and gently warmed. Further, oxalic acid (225 mg) was added in portions till the colour of the permanganate ion disappeared. The quantity of MnCl (in mg) present in the initial solution is (Atomic weights in g mol: Mn = 55, Cl = 35.5)