20 " mL of " `(M)/(60)` `KBrO_3` was added to a sample of `SeO_3^(2-)`, The bromine evolved was removed and the excess of `KBrO_3` was titrated with 5.1 " mL of " `(M)/(25)` solution of `NaAsO_2`. Calculate the amound of `SeO_3^(2-)` and balance the equation.
`SeO_3^(2-)+BrO_3^(ɵ)+H^(o+)toSeO_4^(2-)Br_2+H_2O`
`BrO_3^(ɵ)+AsO_2^(ɵ)+H_2OtoBr^(ɵ)+AsO_4^(3-)+H^(o+)`
`(Br=80, K=39, As=75, Se=79)`

Explanation

To solve the problem step by step, we will follow the outlined process from the video transcript.

### Step 1: Write the balanced equations
We need to balance the two reactions given:

1. **For the oxidation of \( SeO_3^{2-} \) to \( SeO_4^{2-} \)**:
\[
SeO_3^{2-} + BrO_3^{-} + H^{+} \rightarrow SeO_4^{2-} + Br_2 + H_2O
...