Question

Which of the following reactions are disproportionation reactions?
(I) $C{u}^{+}\to C{u}^{2+}+Cu$
(II) $3MnO{}_4{}^{-}+4H^{+}\to 2MnO{}_4^{-}+Mn{O}_2+2H_{2}O$
(III) $2KMn{O}_4\to K_{2}Mn{O}_4+Mn{O}_2+O_2$
(IV) $2MnO{}_4{}^{-}+3M{n}^{2+}+2H_{2}O\to 5Mn{O}_2+4H{}^{+}$

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

Answer 1

The correct option is A (I), (II)

Disproportionation reaction are the reactions in which the same element/compound get oxidized and reduced simultaneously.

Since I and II reactions are as follows

$2C{u}^{+}\to C{u}^{2+}+C{u}^0$

And

$3Mn{O}_4^{2-}4H^{+}\to 2Mn{O}_4^{-}+Mn{O}_2+2H_{2}O$

Other two reactions are correct and belong to comproportionation reaction.

Thus option A is correct.