Assertion: Molar entropy of vaporization of water is different from ethanol.
Reason: Water is more polar than ethanol.

Options

A. If both assertion and reason are true and reason is the explaination of assertion.
B. If both assertion and reason are true but reason is not the correct explaination of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Explanation

To analyze the question, we will break it down into two parts: the assertion and the reason.

### Step 1: Understanding the Assertion
The assertion states that the molar entropy of vaporization of water is different from that of ethanol.

- **Molar Entropy of Vaporization**: This is defined as the amount of energy required to vaporize one mole of a substance at its boiling point, divided by the temperature at which the vaporization occurs.

- **Comparison**: Water and ethanol have different structures and intermolecular forces, which will affect their molar entropy of vaporization.

### Step 2: Understanding the Reason
The reason given is that water is more polar than ethanol.

- **Polarity**: Polarity in molecules affects how they interact with each other, particularly in terms of hydrogen bonding. Water (H₂O) is a highly polar molecule due to its bent shape and the presence of two lone pairs on the oxygen atom, which allows for strong hydrogen bonding.

- **Ethanol (C₂H₅OH)**: Ethanol is also polar but less so than water due to its hydrocarbon (ethyl) group, which reduces the overall polarity of the molecule.

### Step 3: Analyzing the Relationship
While both the assertion and the reason are correct, the reason does not adequately explain the assertion.

- **Hydrogen Bonding**: The difference in molar entropy of vaporization between water and ethanol is primarily due to the extent of hydrogen bonding. Water has a higher degree of hydrogen bonding compared to ethanol, which leads to a greater amount of energy required to vaporize it.

### Conclusion
- **Assertion**: Correct (molar entropy of vaporization of water is indeed different from that of ethanol).
- **Reason**: Correct (water is more polar than ethanol), but it does not directly explain the difference in molar entropy of vaporization.

### Final Answer
The correct answer to the question is **B**: Both the assertion and reason are correct, but the reason is not the correct explanation for the assertion.

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