When `KMnO_(4)` acts as an oxidising agnet and ultimetely from `MnO_(4)^(2-), MnO_(2), Mn_(2)O_(3)`, and `Mn^(2+)`, then the number of electrons transferred in each case, respectively, are

Options

A. ` 1,3,4,5`
B. ` 3,5,7,1`
C. ` 1,5,3,7`
D. ` 4,3,1,5`

Answer

A

Explanation

Let x be the oxidaton number of Mn.
` MnO_4^(2-) rArr x + 4 (-2) =-1`
` x-8 =-1`
`x = + 7`
`MnO_4^(2-) rArr x +4 (-2) =-2`
` x-8= -2`
` x= +6`
`MnO_2 rArr x + 2(-2) =0`
` x-4 =0`
`x rArr +4`
`Mn_2O_3 rArr 2x +3 (-2) =0`
` 2x -6 =0`
` x=+3`
`Mn^(2+) rArr x = +2`
`:. overset(+7) (M)nO_(4)^(-)+e^(-) rarr overset(+6)(M)nO_(4)^(2-)`
`+3e^(-) rarr overset(+4)(M)nO_(2)`
`+4e^(-)rarroverset(+3)(M)n_(2)O_(3)`
`+5e^(-) rarr overset(+2)(M)n^(2+)`