An organic reaction occurs by using reagents called electrophiles and nucleophiles via the formation of some reactive intermediates called carbocations, carbanions, free radicals, carbenes, nitrenes, radical cations, and radical anions.
The most stable free radical is :

Options

A. `PhCH_2 dot C H_2`
B. `Me dot CH_2`
C. `Me_2 dot CH`
D. `Ph dot C HMe`

Explanation

To determine the most stable free radical among the given options, we need to analyze the stability factors that influence free radicals. The stability of free radicals is primarily affected by resonance and the inductive effect from electron-donating groups.

### Step-by-Step Solution:

1. **Identify the Free Radicals**:
We need to analyze the free radicals presented in the options. Let's denote them as:
- Option A: Free radical on a phenyl group (Ph-CH2•)
- Option B: Free radical on a methyl group (CH3-CH•)
- Option C: Free radical on a tertiary carbon (Me2C•)
- Option D: Free radical on a phenyl group with a methyl (Ph-CH•-Me)

2. **Analyze Resonance Effects**:
- **Option A (Ph-CH2•)**: The phenyl group can stabilize the radical through resonance. However, the radical is on a CH2, which does not allow for effective resonance stabilization.
- **Option B (CH3-CH•)**: This is a primary radical and does not have resonance stabilization. It has minimal stability.
- **Option C (Me2C•)**: This is a tertiary radical. Tertiary radicals are more stable due to hyperconjugation and inductive effects from the two methyl groups, but it lacks resonance.
- **Option D (Ph-CH•-Me)**: The radical is on a carbon adjacent to a phenyl group, which allows for resonance stabilization. The methyl group also provides a +I effect, enhancing stability.

3. **Evaluate Inductive Effects**:
- The methyl group in Option D provides a +I effect, which helps in stabilizing the radical. The phenyl group can delocalize the radical through resonance, making it more stable than the others.

4. **Conclusion**:
After evaluating all options, Option D (Ph-CH•-Me) is the most stable free radical due to the combination of resonance stabilization from the phenyl group and the +I effect from the methyl group.

### Final Answer:
The most stable free radical is **Option D (Ph-CH•-Me)**.