Assign $\mathrm{O}.\mathrm{N}.$ (oxidation number) to atoms of only those elements which undergo $\mathrm{O}.\mathrm{N}.$ change in the following redox reaction and then balance the equation.

${\mathrm{IO}}_4^{-}+{\mathrm{I}}^{-}+{\mathrm{H}}^{+}\to {\mathrm{I}}_2+{\mathrm{H}}_2\mathrm{O}$

Assign $\mathrm{O}.\mathrm{N}.$ (oxidation number) to atoms of only those elements which undergo $\mathrm{O}.\mathrm{N}.$ change in the following redox reactions and then balance the equation.

${\mathrm{KMnO}}_4\to {\mathrm{K}}_2{\mathrm{MnO}}_4+{\mathrm{MnO}}_2+{\mathrm{O}}_2$

[Hint: ${\mathrm{KMnO}}_4$ reduces to ${\mathrm{K}}_2{\mathrm{MnO}}_4$ and ${\mathrm{MnO}}_2$ and the change in $\mathrm{O}.\mathrm{N}.=4$]

Assign $\mathrm{O}.\mathrm{N}.$ to atoms of only those elements which undergo $\mathrm{O}.\mathrm{N}.$ change in the following redox reaction and then balance the equation.

${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\to {\mathrm{N}}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{Cr}}_2{\mathrm{O}}_3$

Assign the oxidation number to atoms of only those elements which undergo oxidation number change in the following redox reactions, and then balance the equations.

${\mathrm{MnO}}_4^{2-}+{\mathrm{H}}^{+}\to {\mathrm{MnO}}_4^{-}+{\mathrm{MnO}}_2+{\mathrm{H}}_2\mathrm{O}$

Assign oxidation number to atoms of only those elements which undergo oxidation number change in the following redox reactions, and then balance the equations.

${\mathrm{H}}_3{\mathrm{PO}}_3\to {\mathrm{H}}_3{\mathrm{PO}}_4+{\mathrm{PH}}_3$

Assign oxidation number to atoms of only those elements which undergo oxidation number change in the following redox reactions, and then balance the equations.

$\mathrm{Zn}+{\mathrm{HNO}}_3\to \mathrm{Zn}({\mathrm{NO}}_3{)}_2+{\mathrm{N}}_2\mathrm{O}+{\mathrm{H}}_2\mathrm{O}$

Assign the oxidation number to atoms of only those elements which undergo oxidation number change in the following redox reactions, and then balance the equations.

$\mathrm{CuS}+{\mathrm{NO}}_3^{-}+{\mathrm{H}}^{+}\to {\mathrm{Cu}}^{2+}+{\mathrm{S}}_8+\mathrm{NO}+{\mathrm{H}}_2\mathrm{O}$

Assign oxidation number to atoms of only those elements, which undergo oxidation number change in the following redox reactions, and then balance the equations.

${\mathrm{CuSO}}_4+\mathrm{KI}\to {\mathrm{Cu}}_2{\mathrm{I}}_2+{\mathrm{I}}_2+{\mathrm{K}}_2{\mathrm{SO}}_4$

Assign oxidation number to atoms of only those elements which undergo oxidation number change in the following redox reactions, and then balance the equations.

${\mathrm{FeSO}}_4\to {\mathrm{Fe}}_2{\mathrm{O}}_3+{\mathrm{SO}}_2+{\mathrm{SO}}_3$