Which of the following is an example of a non-ideal solution showing positive deviation?

Options

A. Acetone + Carbon disulphide
B. Chlorobenzene + Bromobenzene
C. Chloroform + Benzene
D. Acetone + Aniline

Answer

To solve the question of identifying an example of a non-ideal solution that shows positive deviation, we can follow these steps:

### Step 1: Understand the Concept of Ideal and Non-Ideal Solutions
- **Ideal Solutions**: These solutions follow Raoult's law perfectly, meaning that the vapor pressure of the solution is directly proportional to the mole fraction of the solvent.
- **Non-Ideal Solutions**: These do not follow Raoult's law perfectly and can show either positive or negative deviations.

### Step 2: Define Positive and Negative Deviation
- **Positive Deviation**: Occurs when the vapor pressure of the solution is greater than expected. This happens when the intermolecular forces between the solute and solvent (A-B interactions) are weaker than those between the solute (A-A) and solvent (B-B).
- **Negative Deviation**: Occurs when the vapor pressure of the solution is lower than expected, indicating that the A-B interactions are stronger than A-A and B-B interactions.

### Step 3: Analyze the Given Options
1. **Option 1: Acetone + Carbon Disulfide** - Known to show positive deviation.
2. **Option 2: Bromobenzene** - This is an example of an ideal solution.
3. **Option 3: Chloroform + Benzene** - This combination shows negative deviation.
4. **Option 4: Acetone + Aniline** - This also shows negative deviation.

### Step 4: Identify the Correct Answer
- From the analysis, **Option 1 (Acetone + Carbon Disulfide)** is the only combination that is a non-ideal solution showing positive deviation.

### Conclusion
The correct answer to the question is **Option 1: Acetone + Carbon Disulfide**.

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