Which of the following does not help to distinguish evaporation and boiling?

Options

A. Temperature at which the phenomenon occurs
B. Portion of the liquid from which they occur
C. Change of state of matter
D. Speed at which they occur

Explanation

To solve the question "Which of the following does not help to distinguish evaporation and boiling?", we need to analyze the options provided and understand the characteristics of both processes.

### Step-by-Step Solution:

1. **Understand Evaporation and Boiling**:
- **Evaporation**: This is a surface phenomenon where molecules at the surface of a liquid gain enough energy to escape into the gas phase. It can occur at any temperature and happens slowly.
- **Boiling**: This is a bulk phenomenon where the entire liquid reaches a specific temperature (boiling point) and changes to gas. For water, this is typically at 100°C at standard atmospheric pressure.

2. **Analyze the Options**:
- **Option 1: Temperature at which the phenomenon occurs**.
- Evaporation can occur at any temperature, while boiling occurs at a specific temperature (e.g., 100°C for water). This option helps distinguish between the two.

- **Option 2: Portion of the liquid from which they occur**.
- Evaporation occurs from the surface of the liquid, while boiling occurs throughout the entire liquid. This option also helps distinguish between the two.

- **Option 3: Change of state of matter**.
- Both evaporation and boiling involve the change of state from liquid to gas. This is the same in both processes and does not help to distinguish between them.

- **Option 4: Speed at which they occur**.
- Evaporation occurs slowly, while boiling happens rapidly. This option helps distinguish between the two.

3. **Identify the Correct Answer**:
- Since option 3 ("Change of state of matter") is the only option that does not help to distinguish between evaporation and boiling, it is the correct answer.

### Final Answer:
**Option 3: Change of state of matter** does not help to distinguish evaporation and boiling.