36. Solving a chemistry problem

84. The iron ions contained in the solution were previously reduced to Fe 2, and then titrated with a working solution of potassium permanganate with a molar equivalent concentration of 0.09 mol-eq / l. Calculate the concentration of total iron in the solution (g/l) if 5.45 ml of potassium permanganate solution is used for titration of 50 ml of the solution.
Write down the reaction equation; indicate the type of titration, indicator (if necessary); what is titration, how long does it take?