JEE Advanced 2013 Paper 2

The reactions of Cl‌2 gas with cold - dilute and hot - concentrated NaOH in water give sodium salts to two(different) oxoacids of chlorine, P and Q , respectively. The Cl‌2 gas reacts with SO‌2 gas, in presence of charcoal, to give a product R. R reacts with white phosphorus to give a compound S. On hydrolysis, S gives an oxoacid of phosphorus T