In which of the following reactions conc. H2SO4 is used as an oxidising reagent? (i) CaF2+ H2SO4 → CaSO4+ 2HF (ii) 2HI + H2SO4 → I2 + SO2+ 2H2O (iii) Cu + 2H2SO4 → CuSO4 + SO2 + 2H2O (iv) NaCl + H2SO4 → NaHSO4 + HCl
Among the above four (B) and (C) represent the oxidizing behavior of H2SO4. In (B) reaction it oxidizes HI and itself reduces to SO2 oxidation state of central atom sulphur decreases from +6 to +4. In (C) it oxidizes copper and itself gets reduced to SO2
