Pick out the correct statement(s):

Options

A. `MnO_(2)` dissolves in conc.HCl but does not form `Mn^(4+)` ions
B. Decomposition of acidic `KMnO_(4)` is not catalyst by sunlight
C. `MnO_(4)^(2-)` is stongly oxidising and stable only in very strong alkali. In dilute alkali, water or acidic solutions it disproportionates
D. `KMnO_(4)` does not act as oxidising agent in alkaline medium

Answer

A, C

Explanation

(a)`MnO_(2)+4HCl to MnCl_(2)+Cl_(2)+2H_(2)O`
(b)Decomposition of acidic `KMnO_(4)` is catalyst by sunlight
`MnO_(4)^(-)+4H^(+) to 4MnO_(4)+2H_(2)O+3O_(2)`
(c)`underset("green")(3K_(2)MnO_(4))+2H_(2)O to underset("purple")(2KMnO_(4)^(-)+underset("dark brown")(MnO_(2))(darr)+4KOH`
(d) `KMnO_(4)` also acts as an oxidizing agent in alkaline medium.
`MnO_(4)^(-)+2H_(2)O +3e^(-) to MnO_(2)+4OH^(-), E^(@)=+1.23` volt