The correct combination from the following given statements about chemisorption
I) It is unilayered adsorption
II) It is irreversible and takes place slowly
III) It occurs rapidly
The correct combination is 

Options

A. Both I and II are correct
B. Both II and III are correct
C. Both I and III are correct
D. All are correct

Answer

To solve the question regarding the correct combination of statements about chemisorption, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement I: It is unilayered adsorption.**
- Chemisorption is characterized by the formation of a single layer of adsorbate on the surface of the adsorbent. This is because it involves the formation of strong chemical bonds between the adsorbate and the surface. Therefore, this statement is **correct**.

2. **Statement II: It is irreversible and takes place slowly.**
- Chemisorption is indeed irreversible because once the chemical bonds are formed, the adsorbate cannot easily be removed from the surface. However, the assertion that it takes place slowly is incorrect. Chemisorption typically occurs rapidly as the chemical bonds form quickly upon contact. Thus, this statement is **partially correct** (the irreversibility is correct, but the slow process is incorrect).

3. **Statement III: It occurs rapidly.**
- As mentioned earlier, chemisorption occurs rapidly due to the formation of strong chemical bonds. Therefore, this statement is **correct**.

### Conclusion:
Based on the analysis:
- Statement I is correct.
- Statement II is partially correct (the irreversible part is correct, but the slow part is incorrect).
- Statement III is correct.

The correct combination of statements about chemisorption is that **I and III are correct**.

### Final Answer:
The correct combination is **I and III**.

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