The maximum ease of abstraction of a hydrogen atom by a chlorine atom is given by :

Options

A. `(CH_3)_3C-CH_3`
B. `(CH_3)_2CH_2`
C. `C_6H_5CH_3`
D. `CH_2=CHCH_3`

Answer

To determine the maximum ease of abstraction of a hydrogen atom by a chlorine atom, we need to analyze the stability of the radical intermediates formed after hydrogen abstraction from different compounds. The stability of these radicals will dictate how easily a hydrogen atom can be abstracted.

### Step-by-Step Solution:

1. **Identify the Compounds**: We are given four compounds from which we will abstract a hydrogen atom using a chlorine atom. The compounds are:
- (1) C(CH3)4 (tert-butyl)
- (2) CH3CH(CH3)2 (isopropyl)
- (3) C6H5CH3 (toluene)
- (4) CH2=CH-CH3 (propene)

2. **Analyze the First Compound (tert-butyl)**:
- When we abstract a hydrogen atom from tert-butyl (C(CH3)4), we form a tertiary radical (C(CH3)3•).
- Tertiary radicals are highly stable due to the +I (inductive) effect of the three methyl groups, which donate electron density to the radical center.

3. **Analyze the Second Compound (isopropyl)**:
- For isopropyl (CH3CH(CH3)2), we form a secondary radical (CH3C•H(CH3)).
- Secondary radicals are less stable than tertiary radicals because they have only two +I groups contributing to their stability.

4. **Analyze the Third Compound (toluene)**:
- In toluene (C6H5CH3), abstraction of a hydrogen atom leads to a benzyl radical (C6H5CH2•).
- Benzyl radicals are stabilized by resonance, as the unpaired electron can be delocalized into the aromatic system, making them quite stable.

5. **Analyze the Fourth Compound (propene)**:
- For propene (CH2=CH-CH3), abstraction leads to an allylic radical (CH2=CH-CH2•).
- Allylic radicals are also stabilized by resonance, but they are generally less stable than benzyl radicals.

6. **Compare the Stability of Radicals**:
- Tertiary radical (tert-butyl) > Benzyl radical (toluene) > Secondary radical (isopropyl) > Allylic radical (propene).
- The most stable radical is the tertiary radical from tert-butyl, followed by the benzyl radical from toluene.

7. **Conclusion**:
- The maximum ease of abstraction of a hydrogen atom by a chlorine atom occurs from the compound that forms the most stable radical.
- Therefore, the answer is **C6H5CH3 (toluene)**, as it leads to the most stable radical due to resonance stabilization.