Chemisorption, also known as chemical adsorption or activated adsorption, is a process in which a chemical bond is formed between gaseous molecules or atoms and the surface of a solid. This process requires a significant amount of energy, making it distinct from physisorption, where weak van der Waals forces are involved.

Explanation:

1. Chemisorption and the formation of chemical bonds:
- Chemisorption is characterized by the formation of chemical bonds between the adsorbate (gaseous molecules or atoms) and the adsorbent (solid surface).
- This bond formation is a result of the interaction between the electrons in the adsorbate and the surface atoms or ions of the adsorbent.
- The chemical bonds can be covalent or ionic in nature, depending on the nature of the adsorbate and the surface.

2. Energy requirement in chemisorption:
- Chemisorption requires a relatively high amount of energy compared to physisorption.
- This energy is needed to overcome the activation energy barrier associated with the formation of chemical bonds.
- The activation energy barrier arises from the need to break existing bonds in the adsorbate and the adsorbent to allow the formation of new bonds.
- The energy required for chemisorption is typically several orders of magnitude higher than the thermal energy available at room temperature.

3. Terms used to describe chemisorption:
- Chemisorption is often referred to as chemical adsorption because it involves the formation of chemical bonds.
- It is also called activated adsorption because the process requires activation energy to overcome the energy barrier for bond formation.
- The term "positive adsorption" is not commonly used to describe chemisorption and is not an accurate description of the process.

In conclusion, chemisorption is a process in which chemical bonds are formed between gaseous molecules or atoms and the surface of a solid. This process requires a significant amount of energy and is often referred to as chemical adsorption or activated adsorption.