The correct order of reactivity among
I (atomic hydrogen), II (Dihydrogen) and III (Nascent hydrogen) is

Options

A. `I gt II gt III`
B. `I gt III gt II`
C. `II gt III gt I`
D. `III gt II gt I`

Explanation

To determine the correct order of reactivity among atomic hydrogen (I), dihydrogen (II), and nascent hydrogen (III), we can analyze the properties and reactivity of each form of hydrogen.

### Step-by-Step Solution:

1. **Identify the Forms of Hydrogen**:
- **Atomic Hydrogen (I)**: This is represented as H. It exists as individual hydrogen atoms.
- **Dihydrogen (II)**: This is represented as H₂. It is the molecular form of hydrogen, consisting of two hydrogen atoms bonded together.
- **Nascent Hydrogen (III)**: This refers to hydrogen that is in an excited state, often produced during chemical reactions, and is highly reactive.

2. **Reactivity of Atomic Hydrogen (I)**:
- Atomic hydrogen is highly reactive because it has unpaired electrons and can readily participate in chemical reactions. It can easily form bonds with other elements or molecules.

3. **Reactivity of Dihydrogen (II)**:
- Dihydrogen (H₂) is relatively stable due to the strong bond between the two hydrogen atoms. It is less reactive compared to atomic hydrogen because it needs to dissociate into atomic hydrogen before it can react.

4. **Reactivity of Nascent Hydrogen (III)**:
- Nascent hydrogen is considered to be in an excited state and is more reactive than dihydrogen but less reactive than atomic hydrogen. It can readily participate in reactions but is not as reactive as atomic hydrogen.

5. **Order of Reactivity**:
- Based on the analysis:
- Atomic Hydrogen (I) is the most reactive.
- Nascent Hydrogen (III) is moderately reactive.
- Dihydrogen (II) is the least reactive.

Thus, the correct order of reactivity is:
**I (Atomic Hydrogen) > III (Nascent Hydrogen) > II (Dihydrogen)**.

### Final Answer:
The correct order of reactivity among atomic hydrogen, dihydrogen, and nascent hydrogen is:
**I > III > II**.