Some Basic Concepts of Chemistry - Result Question 14
####14. The number of moles of $KMnO_4$ that will be needed to react with one mole of sulphite ion in acidic solution is
[2007]
(a) $4 / 5$
(b) $2 / 5$
(c) 1
(d) $3 / 5$
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Solution:
- (b) The balance chemical equation is :
$ \begin{aligned} & 2 MnO_4^{-}+6 H^{+}+ 5 SO_3{ }^{2-} \\ & 2 Mn^{2+}+5 SO_4{ }^{2-}+3 H_2 O \end{aligned} $
From the equation it is clear that
Moles of $MnO_4^{-}$require to oxidise 5 moles of $SO_3{ }^{2-}$ are 2
Moles of $MnO_4^{-}$require to oxidise 1 mole of $SO_3{ }^{2-}$ are $2 / 5$.
