Question

When $KMn{O}_4$ reacts with $KBr$ in alkaline medium gives bromate ion. Then oxidation state of $Mn$ changes from $+7$ to :

• A. $+6$
• B. $+4$
• C. $+3$
• D. $+2$

Answer 1

Answer: (B)

$+4$

$\stackrel{+7}{2Mn{O}_4^{-}}+B{r}^{-}+H_{2}O\to \stackrel{+4}{2Mn{O}_2}+Br{O}_3^{-}+2O{H}^{-}$

$\therefore$ Oxidation state changes to +4.