Which of the following reactions are disproportionation reactions ?
(I) `Cu^(+)toCu^(2+)+Cu`
(II) `3MnO_4^(-)+4H^(+)to2MnO_4^(-)+MnO_2+2H_2O`
(III) `2KMnO_4 to K_2MnO_4+MnO_2+O_2`
(IV) `2MnO_4^(-)+3Mn^(2+)+2H_2Oto5MnO_2+4H^(+)`

Options

A. (i),(ii)
B. (i),(ii),(iii)
C. (ii),(iii),(iv)
D. (i),(iv)

Answer

A

Explanation

`(i) Cu^(+)` is oxidised to `Cu^(2+)` and reduced to Cu.
In (ii), `MnO_(4)^(2-)` ions are oxidised to `MnO_(4)^(-)` and reduced to `MnO_(2)`.