A solution that shows negative deviation from Raoult’s Law among the following is:

Options

A. ethanol-acetone
B. chlorobenzene-bromobenzene
C. chloroform-acetone
D. benzene-toluene

Answer

To determine which solution shows a negative deviation from Raoult's Law, we need to understand the concepts of ideal and non-ideal solutions, as well as the factors that contribute to deviations from Raoult's Law.

### Step-by-Step Solution:

1. **Understanding Raoult's Law**:
- Raoult's Law states that the vapor pressure of an ideal solution is directly proportional to the mole fraction of the solvent present in the solution. This means that for an ideal solution, the interactions between the molecules of different components are similar to those in the pure components.

2. **Identifying Ideal and Non-Ideal Solutions**:
- Ideal solutions are those that obey Raoult's Law, while non-ideal solutions do not. Non-ideal solutions can show either positive or negative deviations from Raoult's Law.
- Positive deviation occurs when the intermolecular forces between different components are weaker than those in the pure components.
- Negative deviation occurs when the intermolecular forces between different components are stronger than those in the pure components.

3. **Analyzing the Given Options**:
- We have the following pairs to analyze:
- Ethanol and Acetone
- Chlorobenzene and Bromobenzene
- Chloroform and Acetone
- Benzene and Toluene

4. **Evaluating Each Pair**:
- **Ethanol and Acetone**: Ethanol has strong hydrogen bonding. When mixed with acetone, the hydrogen bonding is disrupted, leading to weaker interactions. This results in a positive deviation from Raoult's Law.
- **Chlorobenzene and Bromobenzene**: Both have similar structures and interactions, thus they behave ideally and do not show deviations.
- **Chloroform and Acetone**: Chloroform can form hydrogen bonds with acetone. The interactions between chloroform and acetone are stronger than those in pure chloroform or pure acetone, leading to a negative deviation from Raoult's Law.
- **Benzene and Toluene**: Similar molecular structures lead to ideal behavior, hence no deviation.

5. **Conclusion**:
- Among the options, the pair that shows negative deviation from Raoult's Law is **Chloroform and Acetone**.

### Final Answer:
The solution that shows negative deviation from Raoult’s Law is **Chloroform and Acetone**.