Why can't HBr and HI be prepared by treating conc.H2SO4 with bromide and iodide?
HBr and and HI can't be prepared by treating conc. H2SO4with Bromide and Iodide as HBr and HI are strong reducing agents and they reduce H2SO4into SO2 and themselves into Br2and I2respectively.
i.e.
2NaBr+H2SO4-----------heat--------------> Na2SO4+2HBr
2HBr +H2SO4----------------------------> SO2+2H2O+Br2
2NaI+H2SO4-----------heat-------------->Na2SO4+2HI
2HI+H2SO4----------------------------> SO2+2H2O+I2