An aqueous solution of gas (X) gives the following reactions.
(i) It decolourizes on acidified K2 Cr2 O7 solution.
(ii) On boiling it with H2O2 , cooling it and then adding an aqueous solution of BaCl2 a ppt. insoluble in dilute hydrochloric acid is obtained.
(iii) On passing H2S in the solution, a white turbidity is obtained. Identify (X) and gives equations for the reactions at steps (i),(ii) and (iii).