Question

When kmno4 reacts with br2 in alkaline medium gives bromate ion the oxidation state of mn changes from +7 to?

Answer 1

Answer : The oxidation state of 'Mn' changes from (+7) to (+4)

Explanation :

When permanganate ion reacts with bromine ion in an alkaline medium to give manganese dioxide and bromate ion as a product.

The balanced reaction will be,

$2MnO_4^-+Br^-+H_2O\rightarrow 2MnO_2+BrO_3^-+2OH^-$

The oxidation state of 'Mn' in $MnO_4^-$ and $MnO_2$ are,

For $MnO_4^-$ :

Let the oxidation state of 'Mn' will be 'x'

$x+4(-2)=-1\\\\x=+7$

For $MnO_2$ :

$x+2(-2)=0\\\\x=+4$

Hence, from this we conclude that the oxidation state of 'Mn' changes from (+7) to (+4).