Question

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

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

Answer 1

The correct option is D 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 to be removed. Therefore, $HF$ is a poor reducing agent.