The common fungicide used in preventing growth of fungus on herbarium specimens is

Options

A. Copper sulphate
B. Lime
C. Both A and B
D. Mercuric chloride

Answer

**Step-by-Step Solution:**

1. **Understanding Herbarium Specimens**: A herbarium is a collection of dried and pressed plant specimens that are stored on sheets for future study. These specimens may still be susceptible to fungal and bacterial infections despite being dried.

2. **Identifying the Need for Fungicides**: Since herbarium specimens are at risk of fungal growth, it is essential to use a fungicide to prevent this growth and preserve the specimens effectively.

3. **Common Fungicides**: Various fungicides can be used for this purpose, but it is important to identify the most common one used specifically for herbarium specimens.

4. **Mercuric Chloride as a Fungicide**: The most commonly used fungicide for preventing fungal growth on herbarium specimens is mercuric chloride (HgCl2). It is effective in treating the specimens before they are stored.

5. **Concentration of Mercuric Chloride**: The effective concentration of mercuric chloride used for treating herbarium specimens is typically around 0.1%. This concentration is sufficient to prevent fungal attacks while being safe for the specimens.

6. **Conclusion**: Based on the information gathered, the correct answer to the question is that the common fungicide used in preventing the growth of fungus on herbarium specimens is mercuric chloride (HgCl2).

**Final Answer**: Mercuric chloride (HgCl2).

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