__________ is used to prevent the infection of young plants .

Answer

To solve the question "__________ is used to prevent the infection of young plants," we need to identify the appropriate chemical compound that serves this purpose.

### Step-by-Step Solution:

1. **Understanding the Context**: The question is asking for a substance that is used to prevent infections in young plants. This implies that the answer should be a chemical compound that acts as a fungicide or pesticide.

2. **Identifying Common Compounds**: In agricultural practices, various compounds are used to protect plants from infections. One such compound is ethyl mercury chloride.

3. **Chemical Composition**: Ethyl mercury chloride has the chemical formula C2H5HgCl. It consists of an ethyl group (C2H5), mercury (Hg), and a chloride ion (Cl).

4. **Function of Ethyl Mercury Chloride**: This compound is known for its fungicidal properties, meaning it can kill or inhibit the growth of fungi, which are common pathogens that affect young plants.

5. **Conclusion**: Based on the information gathered, the appropriate word to fill in the blank is "ethyl mercury chloride."

### Final Answer:
Ethyl mercury chloride (C2H5HgCl) is used to prevent the infection of young plants.

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