A black are [x]on fraiment `Na_(2)CO_(3)` in the presence of air gives a green compound (a). When Rreen compound (a) died in water it producess dark precipitate (b) and pink solution (e) crystal of (e) when treated with propene produces dark ppr (b)
Solution `overset (Sa_(2)//H^(+)) to (d) "solution" overset("reagent")underset((R)) to (c)` solution reagent (R) can be used.

Options

A. `OH^(-)//SO_(3)`
B. `H_(2)O""//H^(+)`
C. `PbO_(2)//H^(+)`
D. `Sn^(+2)//H^(+)`

Answer

C

Explanation

`underset((x))(2MnO_(2))2K_(2)CO_(3)+O_(2) to 2K_(2)MnO_(4)+2CO_(4)`
The dark green `K_(2)MnO_(4)` disproportionates in a neutral or acidic solution to give permangante.
`3MnO_(4)^(-2)+4H^(o+) to underset((c))(2MnO_(4)^(-))+ underset((b))(MnO_(2))+2H_(2)O`
`MnO_(2)` is dark precipitate (b)
and `KMnO_(4)` solution is pink solution (c)
When `KMnO_(4)` reacts with propene (unsaturated compounds) it is reduced to `MnO_(2)` (b)
`CH_(3)-CH-=CH_(3) overset("Cold" KMnO_(4)//OH^(-))toCH_(3)- underset(OH) underset(|)(CH)- underset(OH) underset(|)(CH_(2)) underset((b))(MnO_(2))`
`KMnO_(4) + 5SO_(2)+2H_(2)O overset(H^(o+)) to K_(2)SO_(4)+2MnSO_(4)+2H_(2)SO_(4)`
`Mn^(+2) overset("Reagent") underset((R)) to underset((C)) (MnO_(4)^(-))`
The reagent .R. is strong oxidizing agent. `:.R=PbO_(2)//H^(o+)`