<P> The acid facilitates the conversion by the brown, Manganese - containing precipitate of the Iodide ion into elemental Iodine . </P> <P> The Mn (SO) formed by the acid converts the iodide ions into iodine, itself being reduced back to manganese (II) ions in an acidic medium . </P> <Dl> <Dd> Mn (SO) + 2 I (aq) → Mn (aq) + I (aq) + 2 SO (aq) </Dd> </Dl> <Dd> Mn (SO) + 2 I (aq) → Mn (aq) + I (aq) + 2 SO (aq) </Dd>

Determination of dissolved oxygen in water using the winkler method