OXIDES OF SULPHUR: Sulphur burns in oxygen to produce two oxides – sulphur (iv) oxide and sulphur (vi) oxide.
Sulphur (iv) oxide (SO2)
It is produced laboratorily by the heating of sodium or potassium trioxosulphate (iv) with hydrochloric acid.
K2SO3(aq)+ 2HCL(aq) → 2KCL(aq) + H2O(L) + SO2(g)
It is also produced by heating concentrated tetraoxosulphate (vi) acid with copper.