Among the following, select the disproportionation reaction ?

(i) $2\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2 \to 2\mathrm{PbO}+ 4{\mathrm{NO}}_2 + {\mathrm{O}}_2$

(ii) ${\mathrm{I}}_2 \to {\mathrm{I}}^{-} + {\mathrm{IO}}_3^{-}$

(iii) $3{\mathrm{Cl}}_2 + 6\mathrm{NaOH} \to 5\mathrm{NaCl} + {\mathrm{NaClO}}_3 + 3{\mathrm{H}}_2\mathrm{O}$

(iv) ${\mathrm{P}}_4 + 3\mathrm{NaOH} + 3{\mathrm{H}}_2\mathrm{O}\to 3{\mathrm{NaH}}_2{\mathrm{PO}}_2 + {\mathrm{PH}}_3$

A reaction in which the same species is simultaneously oxidized as well as reduced is called a disproportionation reaction.

(ii) $\stackrel{0}{{\mathrm{I}}_2} \to \stackrel{-1}{{\mathrm{I}}^{-}} + \stackrel{+5}{{\mathrm{IO}}_3^{-}}$

(iii) $\stackrel{0}{3{\mathrm{Cl}}_2} + 6\mathrm{NaOH} \to \stackrel{-1}{5\mathrm{NaCl}} + \stackrel{+5}{{\mathrm{NaClO}}_3} + 3{\mathrm{H}}_2\mathrm{O}$

(iv) $\stackrel{0}{{\mathrm{P}}_4} + 3\mathrm{NaOH} + 3{\mathrm{H}}_2\mathrm{O}\to 3{\mathrm{NaH}}_2\stackrel{+1}{\mathrm{P}}{\mathrm{O}}_4 + \stackrel{-3}{\mathrm{P}}{\mathrm{H}}_3$