What volume of `0.2` M `K_2Cr_2O_7` is required to oxidise 50 " mL of " `0.3 M` `Na_2C_2O_4` in acidic medium?

Explanation

To solve the problem of determining the volume of `0.2 M K_2Cr_2O_7` required to oxidize `50 mL` of `0.3 M Na_2C_2O_4` in acidic medium, we will follow these steps:

### Step 1: Write the half-reactions
In acidic medium, the half-reaction for the oxidation of `Na_2C_2O_4` (oxalate ion) and the reduction of `K_2Cr_2O_7` (dichromate ion) can be written as:

1. **Oxidation half-reaction**:
\[
C_2O_4^{2-} \rightarrow 2 CO_2 + 2 e^-
...