Form HCl HOCl
Chlorine gas escapes
Cl2O
ClO2+H2
Correct option is A. Form HCl HOCl. Cl₂ + H₂O → HCl + HClO. HClO → HCl + [O] (nascent oxygen responsible for bleaching action). Chlorine water loses its yellow colour due to the formation of HCl and HClO.