Question

How many oxyanions among the following show disproportionation?
$Cl{O}^{-},{Cl{O}_2}^{-},{Cl{O}_3}^{-},{Cl{O}_4}^{-}$

Answer 1

$Cl{O}^{-},{Cl{O}_2}^{-}$ and ${Cl{O}_3}^{-}$ shows disproportionation .

$\stackrel{+1}{3Cl{O}^{-}}⟶\stackrel{-1}{2C{l}^{-}}+\stackrel{+5}{{Cl{O}_3}^{-}}$

$\stackrel{+3}{{3Cl{O}_2}^{-}}⟶\stackrel{+5}{{2Cl{O}_3}^{-}}+\stackrel{-1}{C{l}^{-}}$

$\stackrel{+5}{{4Cl{O}_3}^{-}}⟶\stackrel{-1}{C{l}^{-}}+\stackrel{+7}{{3Cl{O}_4}^{-}}$

${Cl{O}_4}^{-}$ does not undergo disproportionation because $Cl$ is present in its highest oxidation state and here cannot oxidize beyond this.