Q61 / 200 · NEET 2007 · Chemistry

The number of moles $\mathrm{KMnO}_4$ that will be needed to react with one mole of sulphite ion in acidic solution is:

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

Solution

The balanced chemical equation is: $2 \mathrm{MnO}_4^{-}+ 6 \mathrm{H}^{+}+5 \mathrm{SO}_3^{--} \longrightarrow 2 \mathrm{Mn}^{++}+5 \mathrm{SO}_4^{--}+3 \mathrm{H}_2 \mathrm{O}$ From the equation it is clear that Moles of $\mathrm{MnO}_4^{-}$ require to oxidise 5 moles of $\mathrm{SO}_3^{--}$are 2 Moles of $\mathrm{MnO}_4^{-}$ require to oxidise 1 mole of $\mathrm{SO}_3^{--}$are $2 / 5$.

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

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