Q52 / 180 · JIPMER 2015 · Chemistry

When $\mathrm{KMnO}_4$ acts as an oxidising agent and ultimately forms $\mathrm{MnO}_4^{2-}, \mathrm{MnO}_2, \mathrm{Mn}_2 \mathrm{O}_3$ and $\mathrm{Mn}^{2+}$, then the number of electrons transferred in each case respectively are

  • Correct answer
    A
    $1,3,4,5$
  • B
    $3,2,1,4$
  • C
    $1,5,3,7$
  • D
    $4,3,2,1$

Solution

$\stackrel{+7}{\mathrm{KMnO}_4} \longrightarrow \stackrel{+6}{\mathrm{MnO}_4^{2-}}$ Transferred electron $=1$ $\begin{gathered}+7 \\ \mathrm{KMnO}_4\end{gathered} \longrightarrow \stackrel{+4}{\mathrm{MnO}_2}$ Number of transferred electrons $=3$ $\stackrel{+7}{\mathrm{KMnO}_4} \longrightarrow \stackrel{+3}{\mathrm{Mn}_2 \mathrm{O}_3}$ Number of transferred electrons $=4$ $\stackrel{+7}{\mathrm{KMnO}_4} \longrightarrow \mathrm{Mn}^{2+}$ Number of transferred electrons $=5$

Hence, the correct answer is option: 'A'.

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