IIT JEE 2008 P1 Q49

how to proceed to such questionss...........is it some common reaction

@nikunj....of all halogens are strong oxidising agents that true..but that's not the correct explanation..coz according to ur explanation Na₂S₂O₃ + I₂ → ....will yield some different products...
@ sanchit..there is no way no proceed in such kinda question if u havent read that reaction b4...btw u may read J D Lee..most of the questions asked in inorganic are from the theory portion of that book....even this one also..

@NIKUNJ HERE HYDROGEN GETS ADDED IN THE PRODUCT. SO ITS REDOX.

hmmm kk