Which of the following solutions is an example of negative deviation from Raoult's law ?

Options

A. Acetone +Ethanol
B. Carbon tetrachloride + Chloroform
C. Acetone + Chloroform
D. Water + Ethanol

Explanation

To determine which solution exhibits negative deviation from Raoult's law, we first need to understand the concept of Raoult's law and what negative deviation means.

### Step 1: Understanding Raoult's Law
Raoult's law states that the vapor pressure of a solution is directly related to the mole fraction of the solvent in the solution. It can be expressed as:
\[ P_{solution} = X_{solvent} \cdot P^0_{solvent} \]
where:
- \( P_{solution} \) = vapor pressure of the solution
- \( X_{solvent} \) = mole fraction of the solvent
- \( P^0_{solvent} \) = vapor pressure of the pure solvent

### Step 2: Defining Negative Deviation
A solution shows negative deviation from Raoult's law when the actual vapor pressure of the solution is less than the vapor pressure predicted by Raoult's law. This occurs when the intermolecular forces between the different components of the solution (AB interactions) are stronger than the forces between the same components in their pure states (AA and BB interactions).

### Step 3: Identifying Stronger Interactions
For a solution to exhibit negative deviation, the interactions between the components (AB) must be stronger than the interactions between the individual components (AA and BB). This typically happens in solutions where hydrogen bonding or strong dipole-dipole interactions are present.

### Step 4: Analyzing the Given Options
Let's analyze the given options. One of the options mentioned is a mixture of acetone (CH3COCH3) and chloroform (CHCl3).

- **Acetone and Chloroform**: When mixed, the interactions between acetone and chloroform (AB interactions) are stronger than the interactions between acetone molecules (AA) and chloroform molecules (BB). This leads to a decrease in vapor pressure, indicating negative deviation from Raoult's law.

### Conclusion
Based on the analysis, the solution that shows negative deviation from Raoult's law is the mixture of acetone and chloroform.

### Final Answer
The correct option is the mixture of acetone (CH3COCH3) and chloroform (CHCl3).

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