The main ore of manganese, pyrolusite, is mainly MnO2. A solution of SnCl2 can be used to estimate the percentage of MnO2 in a sample of pyrolusite, using the following method.*             A known mass of pyrolusite is warmed with an acidified solution containing a known amount of SnCl2.*             The excess Sn2+(aq) ions are titrated with a standard solution of KMnO4.In one such experiment, 0.100g of pyrolusite was warmed with an acidified solution containing 2.00 x 10-3 mol Sn2+. After the reaction was complete, the mixture was titrated with 0.0200 mol dm-3 KMnO4, and required 18.1 cm3 of this solution to reach end point.Balance the following half equations and give balanced overall equationsMnO4-   →           Mn2+                                      and                        MnO2    →           Mn2+Sn2+        →           Sn4+                                                                    Sn2+        →           Sn4+ and use them, and the information above to calculate the percentage of MnO2 in pyrolusite. The percentage is?

A 458 g sample containing Mn3O4 was dissolved and all manganese was converted to Mn2+. In thepresence of fluoride ion, Mn2+ is titrated with 3 lit of KMnO4 solution (which was 1.25 N againstoxalate in acidic medium), both reactants being converted to a complex of Mn(III) , What was the %of Mn3O4 in the sample?

Manganese ions (Mn2+) present in water can be removed by oxidation with chlorine dioxide (ClO2) asshown in the balanced redox reaction below.Mn2+ (aq) + 2ClO2 (aq) + 2H2O (l) ⇌ MnO2 (s) + 2ClO2– (aq) + 4H+ (aq)The reaction is an overall second order reaction with the following rate law:Rate = k[Mn2+][ClO2], where k = 1 x 104 units at pH 7 and 25°C[Mn2+] and [ClO2] are in the units of concentration mol/L.(a) What is the units of the rate constant, k? (1 point)(b) Describe how (i) the reaction rate and (ii) rate constant, k, would change when the concentration ofchlorine dioxide is increased to twice the initial amount (with all other factors remaining the same).(2 points)Page 3 of 3RestrictedOzone is another chemical that can be used to react with manganese in water:Mn2+ (aq) + O3 (g) + 2H2O (l) ⇌ MnO2 (s) + O2 (g) + 2H+ (aq)(c) Based on the reaction equilibrium, should the reaction be carried out at low or high pH for theeffective removal of Mn2+ in water? Briefly explain why. (2 points)(d) Refer the table of Standard Reduction Potential given. Based on the Eo values, name two chlorinecontaining compounds that can be used to react with Mn2+ present in water. (2 points)Reduction Half-Reaction Eo (V)MnO4− (aq) + 8H+ (aq) + 5e− ⇌ Mn2+ (aq) + 4H2O (l) +1.49MnO2 (s) + 4H+ (aq) + 2e−⇌ Mn2+ (aq) + 2H2O (l) +1.21HOCl (aq) + H+ (aq) + e− ⇌ Cl2 (g) + H2O (l) +1.63ClO3− (aq) + 6H+ (aq) + 5e− ⇌ ½Cl2 (g) + 3H2O (l) +1.47ClO4− (aq) + 2H+ (aq) + 2e− ⇌ ClO3− (aq) + H2O (l) +1.19Hg2Cl2 (s) + 2e− ⇌ 2Hg (l) +2 Cl− (aq) +0.27O3 (g) + H2O (l) + 2e− ⇌ O2 (g) +2OH− (aq) +1.24(e) In practice, one of the comparts in Part (d) does not removed manganese (Mn) from watereffectively. Which compound is it and why is it ineffective in the removal of manganese fromwater? (2 points)(f) Mn2+ is reacted to form MnO2 in the reaction shown above. Name one method in which MnO2 canbe removed from water. (1 point)

acid mine drainage poses sever environmental pollution problems due to its high acidity, toxic metals and sulphate contents. the effluent is reported to contain 200 ppb of manganese (mass basis). the effluent flow rate is 500L/hr with a density of 7440 kg/m*3. calculate the mass of Mn that is released from the effluent.

When 0.1 mol MnO2−4 is oxidised the quantity of electricity required to completely MnO2−4 to MnO4− is:

In neutral or faintly alkaline medium KMnO4 being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be: