Question

C2O4-- + I- + H+ ---> I2+CO2+H2O

Answer 1

This won't work. The oxalate ion is loss of electrons and I^- is loss of electrons. In redox equations you must have one half equation losing and one half equation gaining.

[C2O4]^2- ==> 2CO2 + 2e
2I^- ==> I2 + 2e