What is the change in oxidation number of selenium in the following redox reaction? $\mathrm{SeO}_{3 \text {…

What is the change in oxidation number of selenium in the following redox reaction? $\mathrm{SeO}_{3 \text { (aq) }}^{2-}+\mathrm{Cl}_{2(\mathrm{~g})}+2 \mathrm{OH}^{-} \longrightarrow \mathrm{SeO}_{4(\text { (aq) }}^{2-}+2 \mathrm{Cl}_{(\text {(4q) })}^{-}+\mathrm{H}_2 \mathrm{O}$
  1. +2 to -2
  2. -2 to +2
  3. +4 to +6
  4. +3 to +4

Solution

$\begin{array}{|l|l|} \hline \mathrm{SeO}_3^{2-} & \mathrm{SeO}_4^{2-} \\ \hline x+(-2 \times 3)=-2& x+(-2 \times 4)=-2 \\ x=+4 & x=+6 \\ \hline \end{array}$

Asked in: MHT CET 2023 (13 May Shift 1)

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