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 catalysed by sunlight
C. `MnO_(4)^(2-)` is strongly oxidising and stable only in very strong alkalu. In dilute alkali, water or acidic solution it disproportionates
D. `KMnO_(4)` does not act as oxidising agent in alkaline medium

Answer

A, C

Explanation

(a) `MnO_(2)+4HCl rarr MnCl_(2)+cl_(2)+2H_(2)O`
(b) Decomposition of acidic `KMnO_(4)` is catalysed by sunlight.
`4MnO_(4)^(-)+4H^(+)rarr 4MnO_(2)+2H_(2)O+3O_(2)`
(c) `underset("green")(3K_(2)MnO_(4))+2H_(2)Orarrunderset("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^(-)rarrMnO_(2)+4OH^(-),E^(@)=+1.23" volt"`