Question

Which of the following reactions are disproportionation reactions?

(I) $Cu^{+} \rightarrow Cu^{2 +} + Cua$

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

(III) $2KMnO_{4} \rightarrow K_{2}MnO_{4} + MnO_{2} + O_{2}$

(IV) $2MnO_{4}^{-} + 3Mn^{2 +} + 2H_{2}O \rightarrow 5MnO_{2} + 4H^{+}$

• A. (I), (II)
• B. (I), (II), (III)
• C. (II), (III), (IV)
• D. (I), (IV)

Answer 1

Answer: (A)

(I), (II)

Answer 2

In (I), $Cu^{+}$is oxidized as well as reduced. In (II), $MnO_{4}^{-}$ ions are oxidized as well as reduced.