What is the order of reactivity of hydrogen atoms attached to carbon atom in an alkene?

Options

A. `3^(@) gt 1^(@) gt 2^(@)`
B. `2^(@) gt 1^(@) gt 3^(@)`
C. `3^(@) gt 2^(@) gt 1^(@)`
D. `1^(@) gt 2^(@) gt 3^(@)`

Explanation

To determine the order of reactivity of hydrogen atoms attached to carbon atoms in an alkene, we need to consider the structure of alkenes and the influence of the surrounding groups on the reactivity of these hydrogen atoms.

### Step-by-Step Solution:

1. **Understand the Structure of Alkenes**:
- Alkenes are hydrocarbons that contain at least one carbon-carbon double bond (C=C). The general formula for alkenes is CnH2n.

2. **Identify Types of Carbons in Alkenes**:
- In alkenes, the carbon atoms can be classified based on the number of carbon atoms attached to them:
- **Primary (1°) carbon**: A carbon atom bonded to one other carbon.
- **Secondary (2°) carbon**: A carbon atom bonded to two other carbons.
- **Tertiary (3°) carbon**: A carbon atom bonded to three other carbons.

3. **Reactivity of Hydrogen Atoms**:
- The reactivity of hydrogen atoms in alkenes is influenced by the type of carbon they are attached to.
- Tertiary hydrogens (attached to tertiary carbons) are more reactive than secondary hydrogens, which in turn are more reactive than primary hydrogens.

4. **Effect of Electron Donating and Withdrawing Groups**:
- Electron donating groups increase the electron density at the double bond, enhancing the nucleophilic character of the alkene, thus increasing its reactivity.
- Conversely, electron withdrawing groups decrease the electron density, reducing the reactivity.

5. **Order of Reactivity**:
- Based on the above points, the order of reactivity of hydrogen atoms attached to carbon atoms in alkenes is:
- **Tertiary > Secondary > Primary**.
- This means that tertiary hydrogens are the most reactive, followed by secondary hydrogens, and primary hydrogens are the least reactive.

6. **Conclusion**:
- Therefore, the correct order of reactivity of hydrogen atoms attached to carbon atoms in an alkene is tertiary > secondary > primary.