how many mL of 0122M MnO41 are required to react with an exc

how many mL of 0.122M MnO4^-1 are required to react with an excess of C2O4^2- in order to produce 75.25 mL of carbon dioxide gas measured at 30.0 degree c and 715 torr?

MnO4^-(aq) + C2O4^2-(aq) ......> MnO2(s) +CO2(g) (basic solution )

for producing 22.4 l of CO2 1 mole of C2O4^2- is needed so for 75.25 ml = 3.35*10^-3 Mole= 3.35 milimole 7*0.122*x= 3.35= 3.92 ml