Question

When an oxide of manganese (P) is fused with KOH in the presence of an oxidizing agent and dissolved in water, it gives a dark green solution of compound (Q). compound (Q) disproportionate in neutral or acidic solution to give purple compound (R). an alkaline solution of compound (R) oxidizes potassium iodide solution to a compound (S) and compound (P) is also formed compounds P to S are

P Q R S

• A. $MnO_{4}^{-}$ $KIO_{3}$ $MnO_{2}$ $K_{2}MnO_{4}$
• B. $MnO_{2}$ $K_{2}MnO_{4}$ $MnO_{4}^{-}$ $KIO_{3}$
• C. $MnO_{2}$ $MnO_{4}^{-}$ $K_{2}MnO_{4}$ $KIO_{3}$
• D. $K_{2}MnO_{4}$ $MnO_{2}$ $MnO_{4}^{-}$ $KIO_{3}$

Answer 1

Answer: (B)

$MnO_{2}$ $K_{2}MnO_{4}$ $MnO_{4}^{-}$ $KIO_{3}$

Answer 2

$\mathrm { P } = \mathrm { MnO } _ { 2 } , \mathrm { Q } = \mathrm { K } _ { 2 } \mathrm { MnO } _ { 4 } , \mathrm { R } = \mathrm { KMnO } _ { 4 } , \mathrm {~S} = \mathrm { KIO } _ { 3 }$ $\underset{(P)}{2MnO_{2}} + 4KOH + O_{2} \rightarrow \underset{(Q)}{2K_{2}MnO_{4}} + 2H_{2}O$

$3MnO_{4}^{2 -} + 4H^{+} \rightarrow \underset{(R)}{2MnO_{4}^{-}} + MnO_{2} + 2H_{2}O$

$2MnO_{4}^{-} + H_{2}O + KI \rightarrow \underset{(P)}{2MnO_{2}} + 2OH^{-} + \underset{(S)}{KIO_{3}}$