${\mathrm{KMnO}}_4$ oxidises oxalic acid in acidic medium to carbon dioxide. The balanced equation can be represented as follows,

$2{\mathrm{KMnO}}_4+5{\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4+3{\mathrm{H}}_2{\mathrm{SO}}_4\stackrel{}{\to }2{\mathrm{MnSO}}_4+10{\mathrm{CO}}_2+8{\mathrm{H}}_2\mathrm{O}+{\mathrm{K}}_2{\mathrm{SO}}_4$

According to the above balanced equation, 2 moles of potassium permanganate produces the 10 moles of carbon dioxide. The number of ${\mathrm{CO}}_2$ molecules produced per mole of ${\mathrm{KMnO}}_4$ is 5.