What are the following substances ? Give one example of each type .
(i) Antacid
(ii) Nonionic detergents
(iii) Antiseptics

Explanation

To answer the question regarding the substances mentioned, we will define each type and provide an example for each.

### Step-by-Step Solution:

1. **Antacids**:
- **Definition**: Antacids are substances that neutralize stomach acidity. They are commonly used to relieve symptoms such as heartburn, indigestion, or an upset stomach. Antacids work by increasing the pH level in the stomach, thereby reducing acidity.
- **Example**: One common example of an antacid is **magnesium hydroxide** (Mg(OH)₂).

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