Which of the following statements is incorrect ?

Options

A. `NH_3` is more basic than `PH_3`
B. `NH_3` has a higher boiling point than that of HF
C. `N_2` is more inert than `P_4`
D. The dipole moment of `NH_3` is less than that of `SO_2`.

Answer

To determine which statement is incorrect among the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement A: NH3 is more basic than PH3.**
- **Analysis:** Ammonia (NH3) is indeed more basic than phosphine (PH3). This is due to the presence of a lone pair of electrons on nitrogen, which is more available for donation compared to the lone pair on phosphorus. The inert pair effect in PH3 makes the lone pair less available for bonding. Therefore, this statement is **correct**.

2. **Statement B: NH3 has a higher boiling point than HF.**
- **Analysis:** This statement is **incorrect**. Ammonia (NH3) does have hydrogen bonding, but hydrogen fluoride (HF) has stronger hydrogen bonds due to the high electronegativity of fluorine. The boiling point of HF is higher than that of NH3 because the stronger hydrogen bonds in HF require more energy to break. Therefore, this statement is **incorrect**.

3. **Statement C: N2 is more inert than P4.**
- **Analysis:** Nitrogen gas (N2) has a triple bond, which is very strong and makes it quite inert. In contrast, phosphorus (P4) has single bonds that are relatively weaker and can be broken more easily. Thus, N2 is indeed more inert than P4. This statement is **correct**.

4. **Statement D: The dipole moment of ammonia is less than that of SO2.**
- **Analysis:** The dipole moment of ammonia (NH3) is approximately 1.46 D, while that of sulfur dioxide (SO2) is approximately 1.61 D. Since the dipole moment of SO2 is greater than that of NH3, this statement is also **correct**.

### Conclusion:
The incorrect statement among the options is **Statement B**: "NH3 has a higher boiling point than HF."

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