Write a balanced chemical equation for the following reactions:
(i) Permanganate ion (MnO4-) reacts with sulphur dioxide gas in acidic medium to produce Mn2+ and hydrogen sulphate ion. (Balance by ion-electron method)
(ii) The reaction of liquid hydrazine (N2H4) with chlorate ion (ClO-3) in basic medium produces nitric oxide gas and chloride ion in the gaseous state. (Balance by oxidation number method)
(iii) Dichlorine heptaoxide (Cl2O7) in gaseous state combines with an aqueous solution of hydrogen peroxide in acidic medium to give chlorite ion (ClO2-) and oxygen gas.
(Balance by ion-electron method)
(i) 2MnO4- + 5SO2+ 2H2O + H+ → 2Mn2+ + 5HSO4-
(ii) N2H4 + ClO3- → Cl- + NO2 + 2H2O
(iii) Cl2O7 + 4H2O2 → 2ClO2- + 3H2O + 4O2+ 2H+