What is the ratio of `FeC_2O_4` (ferrous oxalate) and ferric oxalate used per " mol of "`Cr_2O_7^(2-)` in acidic medium?

Explanation

`Fe(C_2O_4)` is oxidised to `Fe^(3+)` and `2CO_2` by `Cr_2O_7^(2-)` to `Cr^(3+)`
`{:(Fe^(2+)toFe^(3+)+e^(-)),(C_2O_4^(2-)to2Cr^(3+)+2e^(-)):}]n=3`
`[6e^(-)+Cr_2O_7^(2-)to2Cr^(3+)(n=6)]`
In `Fe+2(CrO_4)_3,Fe^(3+)` is not oxidised but `3 C_2O_4^(2-)` is oxidised to `6CO_2.(SOn=6)`
`Fe(C_2O_4)-=Cr_2O_7^(2-)` `Fe_2(C_2O_4)-=Cr_2O_7^(2-)`
`(1)/(3)mol-=(1)/(6)mol`
`(1)/(6)mol-=(1)/(6)mol`
`=(6)/(3)=2" mol of "FeC_2O_4`
`=1" mol of "Fe_2(C_2O_4)_3`
Ratio of " mol of "`FeC_2O_4` and `Fe_2(C_2O_4)_4=(2)/(1)=2:1`