Which one of the following is a correct statement?

Options

A. Chemisorption is reversible in nature
B. Chemisorption is high at very low temperature
C. Chemisorption depends on the nature of the gas
D. Chemisorption does not involve activation energy

Answer

To determine which statement regarding chemisorption is correct, we need to analyze the characteristics of chemisorption and compare them with the options provided. Here’s a step-by-step solution:

### Step 1: Understand the Definitions
- **Adsorption**: This is the process where particles (gas, liquid, or solid) accumulate on the surface of a solid or liquid, leading to a higher concentration on the surface compared to the bulk.
- **Absorption**: This is when particles penetrate into the bulk of a solid or liquid.

### Step 2: Differentiate Between Physisorption and Chemisorption
- **Physisorption**: This is a type of adsorption where the forces involved are weak van der Waals forces. It is generally reversible.
- **Chemisorption**: This involves the formation of strong chemical bonds between the adsorbate and the adsorbent. It is typically irreversible because breaking these bonds requires significant energy.

### Step 3: Analyze the Statements
1. **Chemisorption is reversible in nature**: This is incorrect. Chemisorption is generally irreversible due to the strong chemical bonds formed.

2. **Chemical reaction is high at very low temperature**: This is also incorrect. Chemical reactions typically require a certain amount of activation energy, which is more readily available at moderate or higher temperatures.

3. **Chemical reaction depends on the nature of the gas**: This statement is correct. The ability of a gas to react chemically with a surface depends on its properties and the conditions present.

4. **Chemical substances do not involve activation energy**: This is incorrect. Chemical reactions require activation energy to occur.

### Conclusion
The correct statement is: **Chemical reaction depends on the nature of the gas**.