Which of the following is not correct for `D_(2)O`

Options

A. Boiling point is higher than `H_(2)O`
B. `D_(2)O` reacts slowly than `H_(2)O`
C. Viscosity is higher than `H_(2)O` at `25^(@)`
D. Solubility of NaCl in it is more than `H_(2)O`

Answer

To determine which statement is not correct for deuterium oxide (D₂O), also known as heavy water, we will analyze the properties of D₂O in comparison to regular water (H₂O).

### Step-by-Step Solution:

1. **Understanding Deuterium Oxide (D₂O)**:
- D₂O is composed of deuterium, an isotope of hydrogen, and oxygen. It is often referred to as heavy water because it contains deuterium, which has a greater mass than regular hydrogen.

2. **Boiling Point Comparison**:
- The boiling point of D₂O is higher than that of H₂O. This is due to the stronger hydrogen bonding in D₂O compared to H₂O, resulting from the greater mass of deuterium.
- **Conclusion**: This statement is correct.

3. **Reactivity**:
- D₂O is less reactive than H₂O. This is because the O-D bond is stronger than the O-H bond, making it less likely to participate in chemical reactions.
- **Conclusion**: This statement is correct.

4. **Solubility**:
- When considering the solubility of ionic compounds like NaCl in D₂O compared to H₂O, it is observed that the solubility of NaCl in D₂O is lower than in H₂O. This is due to the stronger O-D bonds, which make it harder for the D₂O molecules to solvate the Na⁺ and Cl⁻ ions.
- **Conclusion**: This statement is correct.

5. **Identifying the Incorrect Statement**:
- Since the first three statements regarding boiling point, reactivity, and solubility are correct, we need to identify the statement that is not correct.
- If there is an option that states something incorrect about D₂O, such as its properties or behavior compared to H₂O, that would be the answer.

### Final Answer:
The statement that is not correct for D₂O is related to its solubility in comparison to H₂O, specifically that it has higher solubility for NaCl than H₂O, which is incorrect.

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