In which reaction is there a change in the oxidation state?

Explain the balancing of a redox reaction by the half-reaction method with a suitable example.

What is the stoichiometric coefficient of the oxalate ion after balancing the following redox reaction?
$MnO_4^- + C_2O_4^{2-} + H^+ \rightarrow Mn^{2+} + CO_2 + H_2O$

What is the equivalent mass of $IO_4^-$ when it is converted into $I_2$ in an acidic medium?

For the redox reaction $Zn + NO_3^{-} \rightarrow Zn^{+2} + NH_4^{+}$,the coefficients of $NO_3^{-}$,$Zn$,and $H^{+}$ in the balanced equation are respectively:

The values of coefficients to balance the following reaction are
$Cr(OH)_3 + ClO^{-} + OH^{-} \to CrO_4^{2-} + Cl^{-} + H_2O$
Find the coefficients for $Cr(OH)_3$,$ClO^{-}$,$CrO_4^{2-}$,and $Cl^{-}$ respectively.