Question

HBr and HI reduce sulphuric acid, HCl can reduce $KMn{O}_4$ and HF can reduce

• A. $KMn{O}_4$
• B. None of the above
• C. $H_{2}S{O}_4$
• D. $K_{2}C{r}_2{O}_7$

Answer 1

The correct option is B None of the above

HI and HBr (in that order) are the strongest reducing hydracids and hence they reduce $H_{2}S{O}_4$. HCl is quite stable and hence is oxidised by strong oxidising agent like $KMn{O}_4$. HF is not a reducing agent. In the smallest $F^{-}$ ion, the electron which is to be removed during oxidation is closest to the nucleus and therefore most difficult removed. Therefore, HF is not a reducing agent