Classify the following as an acid, a base or amphoteric :
(i) `HSO_4^-` , (ii) `IO^-` , (iii) `HI` , (iv) `OH^-`

Explanation

To classify the given species as an acid, a base, or amphoteric, we will analyze each one based on their ability to donate or accept protons (H⁺ ions).

### Step-by-Step Solution:

1. **Identify HSO₄⁻**:
- HSO₄⁻ can donate a proton (H⁺) to form SO₄²⁻, which means it can act as an acid.
- It can also accept a proton to form H₂SO₄, indicating that it can act as a base as well.
- **Conclusion**: HSO₄⁻ is **amphoteric**.
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