While mixing `H_2 SO_4` with water which of the following precautions should be taken?

Options

A. never add acid to water
B. never add water to acid
C. add the lighter heavier liquid
D. avoid sunlight

Explanation

### Step-by-Step Solution:

1. **Understanding the Reaction**: When mixing sulfuric acid (H₂SO₄) with water, it is important to recognize that this is a dilution process. H₂SO₄ is a strong acid, and when it is mixed with water, a chemical reaction occurs that releases a significant amount of heat.

2. **Exothermic Reaction**: The reaction between H₂SO₄ and water is exothermic, meaning it releases heat. This heat can cause the solution to boil and splatter, which can be dangerous.

3. **Correct Mixing Procedure**: To safely dilute sulfuric acid, you should always add the acid to water, not the other way around. This is because adding water to acid can cause a violent reaction that may lead to splattering or boiling over.

4. **Safety Precautions**:
- Always add acid to water slowly and carefully.
- Use appropriate personal protective equipment (PPE), such as gloves and goggles.
- Conduct the mixing in a well-ventilated area or under a fume hood.

5. **Conclusion**: The safest practice when diluting sulfuric acid is to **never add water to acid**; instead, always add acid to water to minimize the risk of an exothermic reaction causing an accident.