The boiling point of an azeotropic mixture of water and ethyl alcohol is less than that of the theoretical value of water and alcohol mixture. Hence the mixture shows

Options

A. That solution is highly saturated
B. Positive deviation from Raoult's law.
C. Negative deviation from Raoult's law
D. Nothing can be said

Explanation

To solve the question regarding the boiling point of an azeotropic mixture of water and ethyl alcohol, we will analyze the behavior of this mixture in relation to Raoult's law.

### Step-by-Step Solution:

1. **Understanding Azeotropic Mixtures**:
- An azeotropic mixture is a mixture of two or more liquids that has a constant boiling point and composition throughout the distillation process. In this case, we are dealing with water and ethyl alcohol.

2. **Boiling Point Comparison**:
- The question states that the boiling point of the azeotropic mixture is less than the theoretical boiling point of a mixture of water and alcohol. The theoretical boiling point can be calculated based on the individual boiling points of the components and their mole fractions.

3. **Raoult's Law**:
- Raoult's law states that the vapor pressure of a component in a mixture is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture. For ideal solutions, the behavior follows Raoult's law closely.

4. **Positive Deviation from Raoult's Law**:
- A positive deviation from Raoult's law occurs when the vapor pressure of the mixture is greater than what is predicted by Raoult's law. This typically happens when the interactions between different molecules in the mixture are weaker than the interactions between like molecules.

5. **Experimental Observations**:
- In the case of the water and ethyl alcohol mixture:
- The experimental vapor pressure of the mixture is greater than the calculated vapor pressure based on Raoult's law.
- The experimental boiling point of the mixture is lower than the theoretical boiling point.

6. **Conclusion**:
- Since the boiling point of the azeotropic mixture is less than the theoretical value, it indicates that the mixture exhibits positive deviations from Raoult's law. This is due to the weaker interactions between water and ethyl alcohol compared to the interactions within pure components.

### Final Answer:
The mixture shows positive deviations from Raoult's law.

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