Which of the following chemical elements does not make water toxic?

Options

A. Chlorine
B. Fluorine
C. Arsenic
D. Lead

Answer

To solve the question "Which of the following chemical elements does not make water toxic?" we need to analyze the options provided: Chlorine, Fluorine, Arsenic, and Lead.

### Step-by-Step Solution:

1. **Understanding the Options**:
- **Chlorine**: Commonly used in water treatment to kill bacteria and purify water. In controlled amounts, it is not toxic.
- **Fluorine**: Often found in compounds used for dental health, but in high concentrations, it can be toxic.
- **Arsenic**: A well-known toxic element that contaminates water and is harmful to health.
- **Lead**: A heavy metal that is toxic and can cause serious health issues when present in water.

2. **Evaluating Toxicity**:
- **Chlorine**: While it can be harmful in excessive amounts, it is used safely in water treatment processes.
- **Fluorine**: Can be toxic at high levels, particularly in drinking water.
- **Arsenic**: Highly toxic and dangerous even in small amounts.
- **Lead**: Extremely toxic and harmful to human health and the environment.

3. **Conclusion**:
- Among the options, Chlorine is the only chemical element that, when used appropriately, does not make water toxic. It is essential for water purification and is safe in regulated amounts.

### Final Answer:
**Chlorine** does not make water toxic when used in appropriate quantities.

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