When we pass carbon dioxide gas through a green coloured solution of potassium manganate, the colour of solution changes to purple and a brown coloured solid gets precipitated. The green colour of potassium manganate solution also becomes purple when it is subjected to electrolysis using iron electrodes.
The change of colour from green to purple is due to

Options

A. conversion of `Mn^(6+)` to `Mn^(7+)`
B. conversion of `Mn^(6+) `to `Mn^(4+)`
C. conversion of `Mn^(4+)` to `Mn^(7+)`
D. conversion of `Mn^(4+)` to ` Mn^(6+)`

Answer

A

Explanation

The green colour is due to presence of `MnO_(4)^(2-)` which changes to Mno, which has a purple colour.
`underset(("green "Mn^(6+)))(3K_2 MnO_(4) + 2H_2 O + 4CO_2 ) to underset("(purple )" Mn^(7+)) ( 2KMnO_(4) ) + underset("(Brown)" Mn^(4+)) (MnO_(2) + 4 KHCO_3)`