The electrochemical reduction of sulphur dioxide was studied at a glassy carbon electrode in ternary mixtures of acetamide + urea + ammonium nitrate or acetamide + urea + lithium nitrate (25-85-degrees-C) and in molten acetamide at 85-degrees-C. The reduction proceeds via a one-electron, irreversible process at lower temperatures to form SO2.-. The reduction becomes reversible at temperatures exceeding 65-degrees-C. The reduction product SO2.- undergoes rapid dimerization to form dithionite. The dithionite is irreversibly oxidized to SO2 in the reverse scan. Dithionite also undergoes thermal decomposition and the kinetics of the process are evaluated. The parameters D, alphan and k(s,f)0 are reported.