Potassium permanganate (KMnO4) is often used as oxidant in water treatment for oxidation and removal of iron and manganese.

Write balanced equations for the oxidation and reduction reactions when Mn2+ and Fe2+ is oxidised by KMnO4 to MnO2 and Fe3+ respectively. Give the oxidation numbers of all the manganese and iron species and indicate which are oxidised and which reduced in the reactions. (6)

Calculate the theoretical amount of KMnO4 required to oxidise Mn2+ to MnO2. (3)

Give your answer in mg/( MnO4- per mg/( Mn2+. (3)

Calculate the amount of acidity produced in the reaction as mg/( H+ per mg/( Mn2+, as well as the amount of natural alkalinity destroyed in the water (HCO3-) Give your answer in mg/( CaCO3 per mg/( Mn2+ oxidised. (6)

Experimental studies showed that a dosage of 0,75mg/( as MnO4- is required for effective oxidation of iron and manganese in a groundwater. The permanganate is obtained and dosed as a 80% KMnO4 solution with a specific gravity of 1,76 g/m(. Determine the dosage rate (m(/min of 75% KMnO4) for a plant with a flow of 25 M(/day.