AIEEE 2006 Solved Paper

2HI−1+H2

+6

SO4

→I20+

+4

SO2

+2H2O
in this reaction oxidation number of S is decreasing from +6 to +4 hence undergoing reduction and for HI oxidation Number of I is increasing from −1 to 0 hence undergoing oxidation therefore H2SO4 is acting as oxidising agent.