_______is a surface phenomenon, whereas boiling is a_______

Explanation

To answer the question, we need to fill in the blanks with the appropriate terms that describe the processes of evaporation and boiling.

1. **Identify the first blank**: The question states that one process is a surface phenomenon. In chemistry, the process that is recognized as a surface phenomenon is **evaporation**. This is because evaporation occurs at the surface of a liquid where molecules gain enough energy to escape into the vapor phase.

2. **Identify the second blank**: The question then asks for a term that describes the other process, which is boiling. Boiling is characterized as a **bulk phenomenon**. This means that boiling involves the entire volume of the liquid, where molecules throughout the liquid gain energy and transition into the vapor phase.

Putting it all together, the complete sentence is:
**Evaporation is a surface phenomenon, whereas boiling is a bulk phenomenon.**