The number of moles of `KMnO_(4)` needed to react with one mole of `SO_(3)^(2-)` in acidic solution is

Options

A. `4//5`
B. `2//5`
C. 1
D. `3//5`

Answer

b

Explanation

Reduction half reactoin
`MnO_(4)^(-)+8H^(+)+5e^(-)rarrMn^(2+)+4H_(2)O`
Oxdiation half reaction
`SO_(3)^(2-=)+H_(2)OrarrSO_(4)^(2-)+2H^(+)+2e^(-)` sinc 1 mole of `SO_(3)^(2-)` gives `2e^(-)` but reduction of 1 mole of `KmnO_(4)` k requires `5 e^(-)` therefore no of mles of `KMnO_(4)` krequired to react with 1 mole of `SO_(3)^(2-)=2//5`