In neutral or faintly alkaline medium, $\mathrm{KMnO}_{4}$ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be :
Solution
In neutral or Faintly alkaline medium, thiosulphate is oxidised almost quantitatively to sulphate ion according to reaction given below, <br/><br/>$8 \mathrm{MnO}_{4}^{-}+3 \mathrm{~S}_{2} \mathrm{O}_{3}^{2-}+\mathrm{H}_{2} \mathrm{O} \rightarrow 8 \mathrm{MnO}_{2}+6 \mathrm{SO}_{4}^{2-}+2 \mathrm{OH}^{-}$<br/><br/> Here the $\mathrm{Mn}$ changes from $\mathrm{Mn}^{+7}$ to $\mathrm{Mn}^{+4}$
<br/><br/>
Thus overall change in its oxidation number would be of 3 .
About this question
Subject: Chemistry · Chapter: d and f Block Elements · Topic: Properties of Transition Metals
This question is part of PrepWiser's free JEE Main question bank. 155 more solved questions on d and f Block Elements are available — start with the harder ones if your accuracy is >70%.