Which of following statements are incorrect about Henry's law ?

Options

A. It is applicable at all P as well as concentration
B. It is applicable at all temperature
C. Solubility of `N_2, NH_3, O_2`,HCl in water can be explained by Henry's law.
D. Raoult's law is special case of Henry's law

Explanation

To determine which statements about Henry's law are incorrect, we need to analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Statement 1: Henry's law is applicable at all pressure as well as concentration.**
- **Analysis:** This statement is incorrect. Henry's law is only applicable under conditions of low pressure and low concentration. At high pressures and concentrations, deviations from Henry's law occur due to interactions between gas molecules and solvent.
- **Conclusion:** Statement 1 is incorrect.

2. **Statement 2: It is applicable at all temperatures.**
- **Analysis:** This statement is also incorrect. Henry's law is applicable only at low temperatures. At high temperatures, the solubility of gases decreases, and the law may not hold true due to increased kinetic energy of the gas molecules, which can lead to greater escape tendencies from the solvent.
- **Conclusion:** Statement 2 is incorrect.

3. **Statement 3: Solubility of N2, NH3, O2, HCl in water can be explained by Henry's law.**
- **Analysis:** This statement is incorrect as well. While NH3 and HCl are soluble in water and their solubility can be explained by Henry's law, N2 and O2 do not dissolve significantly in water under normal conditions (they exist in molecular form and do not ionize). Therefore, Henry's law cannot adequately explain the solubility of N2 and O2 in water.
- **Conclusion:** Statement 3 is incorrect.

4. **Statement 4: Raoult's law is a special case of Henry's law.**
- **Analysis:** This statement is correct. Raoult's law can be considered a special case of Henry's law when the solute is a volatile component and the vapor pressure of the solute is equal to the Henry's constant. This means that Raoult's law applies under specific conditions that align with Henry's law.
- **Conclusion:** Statement 4 is correct.

### Final Answer:
The incorrect statements about Henry's law are:
- Statement 1
- Statement 2
- Statement 3