Draw the structures of the following :
(i) `H_(2)S_(2)O_(8)`
(ii) `HClO_(4)`
(b) How would you account for the following :
(i) `NH_(3)` is a stronger base than `PH_(3)`.
(ii) Sulphur has a greater tendency for catenation than oxygen.
(iii) `F_(2)` is stronger oxidising agent than `Cl_(2)`.

Explanation

### Step-by-Step Solution

#### (i) Structure of `H2S2O8` (Peroxy Disulfuric Acid)

1. **Identify the Atoms and Their Valence Electrons**:
- Sulfur (S) has 6 valence electrons.
- Oxygen (O) has 6 valence electrons.
- Hydrogen (H) has 1 valence electron.
...