For the redox reaction MnO 4 - + C 2 O 4 2 - + H + → Mn 2 + + CO 2 + H 2 O , the correct coefficients…

For balancing the reaction four steps should be followed in the given order

 $1.$ Balance elements i.e central metal which oxidised or reduced.

 $2.$ Balance oxygen by adding water molecules.

 $3.$ Balance hydrogen by adding ${\mathrm{H}}^{+}$ ion.

 $4.$ Balance charge by adding electrons.

Balancing of reaction is given below:

$2{\mathrm{KMnO}}_4+5{\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4+3{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{K}}_2{\mathrm{SO}}_4+2{\mathrm{MnSO}}_4+10{\mathrm{CO}}_2+8{\mathrm{H}}_2\mathrm{O}$
${{\mathrm{MnO}}_4}^{-}=-2$
${\mathrm{C}}_2{{\mathrm{O}}_4}^{-2}=5$
${\mathrm{H}}^{+}=16$

Thus, the correct coefficients of ${{\mathrm{MnO}}_4}^{-}, {\mathrm{C}}_2{{\mathrm{O}}_4}^{-2}$ and ${\mathrm{H}}^{+}$ are $2, 5 \text{and} 16$ respectively.