Some of the major used of heavy water are given below. Which one is not correct?

Options

A. It is used as a moderator in nuclear reactors.
B. It is used as a tracer compound for studying reaction mechanism.
C. High concentration of heavy water accelerates the growth of plants.
D. It is used in preparing deuterium.

Explanation

To determine which statement about the uses of heavy water (D2O) is not correct, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Heavy Water (D2O)**:
- Heavy water is water in which the hydrogen atoms are replaced by deuterium, an isotope of hydrogen. It is denser than regular water and has different physical and chemical properties.

2. **Analyzing Each Option**:
- **Option A**: "It is used as a moderator in nuclear reactors."
- This statement is **correct**. Heavy water is indeed used as a neutron moderator in nuclear reactors to slow down neutrons, allowing for a sustained nuclear reaction.

- **Option B**: "It is used as a tracer compound for studying reaction mechanisms."
- This statement is also **correct**. Heavy water can be used as a tracer in chemical reactions to study mechanisms because it can replace regular water in reactions without significantly altering the reaction conditions.

- **Option C**: "High concentration of heavy water accelerates the growth of plants."
- This statement is **incorrect**. In fact, high concentrations of heavy water can be harmful to plants and may retard their growth. Heavy water can disrupt biological processes because of its different properties compared to regular water.

- **Option D**: "It is used in preparing deuterium."
- This statement is **correct**. Heavy water can be used to produce deuterium, which is an isotope of hydrogen.

3. **Conclusion**:
- The statement that is not correct is **Option C**: "High concentration of heavy water accelerates the growth of plants."

### Final Answer:
**Option C** is the statement that is not correct regarding the uses of heavy water.