`25 mL ` of `H_(2)O_(2)` solution were added to excess of acidified solution of `KI`. The iodine so liberated required `20 mL` of `0.1N Na_(2)S_(2)O_(3)` for titration Calculate the strength of `H_(2)O_(2)` in terms of normalility, percentage and volumes.
(b) To a `25 mL H_(2)O_(2)` solution, excess of acidified solution of `KI` was added. The iodine liberated required `20 mL` of `0.3N` sodium thiosulphate solution. Calculate the volume strength of `H_(2)O_(2)` solution.

Explanation

To solve the problem step by step, we will break down the calculations for both parts of the question regarding the strength of the `H₂O₂` solution.

### Part (a)

1. **Understanding the Reaction**:
- When `H₂O₂` reacts with `KI`, it liberates iodine (`I₂`). The reaction can be summarized as:
\[
H_2O_2 + 2KI \rightarrow 2K^+ + I_2 + 2H_2O
...