Question

Which of the following samples of reducing agents is /are chemically equivalent to 25mL of 0.2 N `KMnO_(4)` to be reduced to `Mn^(2+)` and water?
A. 25 ml of `0.2M FeSO_(4)` to be oxidised to `Fe^(3+)`
B. 50ml of `0.1M H_(3)AsO_(3)` to be oxidised to `H_(3)AsO_(4)`
C. 25 ml of `0.1M SO_(3)^(2-)` to be oxidised to `SO_(4)^(2-)`
D. 25 ml of `0.1M SnCl_(2)` to be oxidised to `SnCl_(4)`

Answer 1

Correct Answer - A::C::D
`MnO_(4)^(-) overset(H^(+))rarr Mn^(2+)` (n-factor =5)
m eqts of `MnO_(4)^(-)` used `=25 xx 0.2 = 5`
(A) m eqts of `FeSO_(4) = 25 xx .2 = 5`
(B) m eqts of `H_(3)AsO_(3) = 50 xx 0.2 = 10`
`[H_(3)AsO_(3) rarr H_(3)AsO_(4)` (n-factor =2)
(C) m eqts of `SO_(3)^(2-) -= 25 xx 0.2 = 5`
`[SO_(3)^(2-) rarr SO_(4)^(2-)`, n-facor =2]
(D) m.eqts of `SnCl_(2) = 25 xx 0.2 = 5`
`[Sn^(2+) rarr Sn^(4+)`, n-factor =2]