Considering the formation, breaking and stregth of hydrogen bond, pradict which of the following mixture will show a positive devition from Raoult's law?

Options

A. Methanol and acetone
B. Chloroform and acetone
C. Nitric acid and water
D. Phenol and aniline

Explanation

To determine which mixture will show a positive deviation from Raoult's law, we need to analyze the intermolecular hydrogen bonding in each of the given mixtures. A positive deviation from Raoult's law occurs when the vapor pressure of the mixture is greater than what would be expected based on the individual components. This typically happens when the intermolecular forces in the mixture are weaker than those in the pure components.

### Step-by-Step Solution:

1. **Identify the Components of Each Mixture**:
- Option 1: Methanol (CH₃OH) and Acetone (C₃H₆O)
- Option 2: Chloroform (CHCl₃) and Acetone (C₃H₆O)
- Option 3: Nitric Acid (HNO₃) and Water (H₂O)
- Option 4: Phenol (C₆H₅OH) and Aniline (C₆H₅NH₂)

2. **Analyze the First Mixture (Methanol and Acetone)**:
- Methanol exhibits strong intermolecular hydrogen bonding.
- When acetone is added, the hydrogen bonds between methanol molecules are disrupted.
- This results in weaker intermolecular forces in the mixture, leading to an increase in vapor pressure.
- Therefore, this mixture shows a positive deviation from Raoult's law.

3. **Analyze the Second Mixture (Chloroform and Acetone)**:
- Chloroform and acetone do not exhibit hydrogen bonding.
- The absence of strong intermolecular forces means that this mixture is unlikely to show a significant deviation from Raoult's law.

4. **Analyze the Third Mixture (Nitric Acid and Water)**:
- Both nitric acid and water can form hydrogen bonds.
- The interactions between nitric acid and water are strong, leading to a decrease in vapor pressure compared to the expected value.
- This mixture shows a negative deviation from Raoult's law.

5. **Analyze the Fourth Mixture (Phenol and Aniline)**:
- Phenol and aniline can form hydrogen bonds, but the strength of these interactions may not be as strong as in the case of methanol.
- However, the presence of hydrogen bonding suggests that this mixture may also show a tendency towards negative deviation due to strong intermolecular forces.

6. **Conclusion**:
- Among the options analyzed, only the mixture of methanol and acetone shows a positive deviation from Raoult's law due to the disruption of hydrogen bonds leading to increased vapor pressure.

### Final Answer:
The mixture that will show a positive deviation from Raoult's law is **Option 1: Methanol and Acetone**.