Which of the following elements is used for the purification of surface water to make it free from germs so that it can be used for drinking purpose?

Options

A. Oxygen
B. Flourine
C. Chlorine
D. Carbon

Explanation

To solve the question regarding which element is used for the purification of surface water to make it free from germs, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Purpose of Water Purification**: The main goal is to make surface water safe for drinking by eliminating germs and pathogens.

2. **Identify Common Water Purification Methods**: One common method for purifying water is the use of chemical agents that can kill bacteria and other microorganisms.

3. **Consider the Options Provided**: The question likely provides several elements or compounds as options. We need to evaluate which of these is commonly used in water purification.

4. **Recognize the Role of Chlorine**: Chlorine (Cl2) is widely known for its use in water treatment. When chlorine is added to water, it forms hypochlorous acid (HClO), which is effective in killing germs.

5. **Understand the Chemical Reaction**: The hypochlorous acid can decompose and release nascent oxygen, which is a strong oxidizing agent. This nascent oxygen is crucial because it helps to oxidize and kill germs present in the water.

6. **Evaluate the Options**:
- Option 1: Oxygen - Not used for purification.
- Option 2: Chlorine - Correct, as it is used for purification.
- Option 3: Chlorine - Repeated option, still correct.
- Option 4: Carbon - Not used for purification.

7. **Conclusion**: Based on the chemical properties and the reactions involved, the correct answer is chlorine.

### Final Answer:
The element used for the purification of surface water to make it free from germs is **Chlorine**.

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