Ethylene glycol gives oxalic acid on oxidation with 

Oxalic acid is formed by oxidation of ethylene glycol with acidified potassium dichromate. 

$\underset{\stackrel{ {\mathrm{CH}}_2\mathrm{OH}}{\mathrm{Ethylene} \mathrm{glycol}}}{\overset{ {\mathrm{CH}}_2\mathrm{OH}}{\mathrm{l}}} + 4\left[\mathrm{O}\right] \underset{{\mathrm{H}}_2{\mathrm{SO}}_4}{\overset{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7}{\to }} \underset{\underset{ \mathrm{Oxalic} \mathrm{acid}}{ \mathrm{COOH}}}{\overset{ \mathrm{COOH}}{\mathrm{l}}} + 2{\mathrm{H}}_2\mathrm{O}$