Calcium dihydrogen salt of `EDTA` is used as an antidote for the poisoning of_________.

Answer

To solve the question regarding the antidote properties of calcium dihydrogen salt of EDTA, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding EDTA**:
- EDTA stands for Ethylene Diamine Tetraacetic Acid. It is a hexadentate ligand, which means it can bind to a metal ion at six different sites.

2. **Structure of EDTA**:
- The structure of EDTA consists of two amine groups and four acetate groups. The acetate groups can donate lone pairs to form coordinate bonds with metal ions.

3. **Role of Calcium Dihydrogen Salt of EDTA**:
- The calcium dihydrogen salt of EDTA is used in medicine as it helps in chelation therapy. Chelation therapy involves the binding of metal ions to form a stable complex, which can then be excreted from the body.

4. **Lead Poisoning**:
- Lead is a toxic heavy metal that can cause serious health issues when accumulated in the body. The calcium dihydrogen salt of EDTA is specifically effective in treating lead poisoning.

5. **Mechanism of Action**:
- When administered, the calcium dihydrogen salt of EDTA binds to lead ions in the bloodstream, forming a soluble EDTA-lead complex. This complex is more soluble than lead alone, allowing it to be excreted through urine.

6. **Importance of Calcium**:
- Using the calcium dihydrogen salt ensures that calcium ions are not removed from the body during the chelation process. This is important for maintaining essential physiological functions.

7. **Conclusion**:
- Therefore, the calcium dihydrogen salt of EDTA is used as an antidote for the poisoning of **lead**.

### Final Answer:
Calcium dihydrogen salt of EDTA is used as an antidote for the poisoning of **lead**.

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