A : Evaporation occurs at any temperature whereas the boiling point depends on the external pressure.
R : Evaporation of a liquid occurs from the surface of a liquid at all temperature whereas boiling takes place at a temperature determined by the external pressure.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then Mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4).

Answer

To analyze the given assertion and reason, let's break it down step by step.

### Step 1: Understand the Assertion
The assertion states that "Evaporation occurs at any temperature whereas the boiling point depends on the external pressure."

- **Evaporation** is a process where molecules at the surface of a liquid gain enough energy to enter the gas phase. This can happen at any temperature, as long as some molecules have sufficient energy to overcome intermolecular forces.
- **Boiling**, on the other hand, is a specific phase transition that occurs when the vapor pressure of the liquid equals the external pressure surrounding the liquid. This means that the boiling point is not a fixed temperature; it changes with variations in external pressure.

### Step 2: Understand the Reason
The reason states that "Evaporation of a liquid occurs from the surface of the liquid at all temperatures whereas boiling takes place at a temperature determined by the external pressure."

- This statement accurately describes the processes of evaporation and boiling. Evaporation happens at the surface and can occur at any temperature, while boiling occurs throughout the liquid when the temperature reaches a certain point, which is influenced by the external pressure.

### Step 3: Evaluate the Assertion and Reason
Both the assertion and the reason are correct statements regarding the processes of evaporation and boiling. The reason provided gives a clear explanation of why the assertion is true.

### Conclusion
Since both the assertion and the reason are correct, and the reason correctly explains the assertion, we can conclude that:

**Both A and R are correct, and R is the correct explanation of A.**

### Final Answer
The correct option is: **Option 1** (Both A and R are correct, and R is the correct explanation of A).

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