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 concept of Raoult's Law and the conditions that lead to negative and positive deviations.

### Step-by-Step Solution:

1. **Understand Raoult's Law**:
Raoult's Law states that the partial vapor pressure of each component in a solution is directly proportional to its mole fraction in the solution. Mathematically, it can be expressed as:
\[ P_A = X_A \cdot P_{A0} \]
\[ P_B = X_B \cdot P_{B0} \]
where \( P_A \) and \( P_B \) are the partial pressures of components A and B, \( X_A \) and \( X_B \) are their mole fractions, and \( P_{A0} \) and \( P_{B0} \) are their vapor pressures in pure form.

2. **Identify Deviations**:
- **Positive Deviation**: Occurs when the vapor pressure of the solution is higher than predicted by Raoult's Law. This typically happens when the interactions between different molecules are weaker than those in the pure components.
- **Negative Deviation**: Occurs when the vapor pressure of the solution is lower than predicted by Raoult's Law. This usually happens when strong interactions (like hydrogen bonding) form between different molecules, making it harder for them to escape into the vapor phase.

3. **Analyze the Given Options**:
- **Option A: Ethanol + Acetone**: This combination shows positive deviation due to the disruption of hydrogen bonding when mixed.
- **Option B: Chlorobenzene + Bromobenzene**: These are similar compounds that behave ideally, showing no deviation from Raoult's Law.
- **Option C: Acetone + Chloroform**: This combination forms hydrogen bonds between the molecules, leading to a lower vapor pressure than predicted by Raoult's Law, indicating negative deviation.

4. **Conclusion**:
Based on the analysis, the solution that shows negative deviation from Raoult's Law is **Acetone + Chloroform** (Option C).

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

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