Which of the following compounds prossesses the `C-H` bonds with the lowest bond dissociation energy?

Options

A. Toluene
B. Benzene
C. n-pentane
D. 2,2- dimethylpropane

Explanation

To determine which compound possesses the `C-H` bonds with the lowest bond dissociation energy, we need to analyze the stability of the resulting carbon radicals formed when the `C-H` bonds are cleaved. The more stable the carbon radical, the lower the bond dissociation energy.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to analyze the compounds given in the question. Let's assume the compounds are:
- A: Toluene
- B: Benzene
- C: n-Pentane
- D: 2,2-Dimethylpropane

2. **Understand Bond Dissociation Energy**: The bond dissociation energy (BDE) is the energy required to break a bond. A lower BDE indicates that the bond is weaker and easier to break, which often correlates with the stability of the resulting radical.

3. **Analyze the Free Radicals**:
- **Compound A (Toluene)**: When the `C-H` bond in toluene is broken, it forms a benzyl radical. This radical is stabilized by resonance, making it relatively stable.
- **Compound B (Benzene)**: The radical formed from benzene is less stable because it is formed from an sp² hybridized carbon, which is less able to stabilize the radical due to its electronegativity.
- **Compound C (n-Pentane)**: The radical formed from n-pentane is a primary radical, which is less stable. However, it can be slightly stabilized by hyperconjugation from adjacent C-H bonds.
- **Compound D (2,2-Dimethylpropane)**: The radical formed here is a tertiary radical, which is relatively stable due to hyperconjugation and inductive effects.

4. **Compare Stability**:
- Toluene (A) has a stable benzyl radical due to resonance.
- Benzene (B) has an unstable radical due to the sp² hybridization.
- n-Pentane (C) has a primary radical, which is less stable.
- 2,2-Dimethylpropane (D) has a tertiary radical, which is more stable than the primary radical.

5. **Conclusion**: Since the stability of the radical formed from toluene is the highest due to resonance stabilization, the `C-H` bond in toluene will have the lowest bond dissociation energy. Therefore, the answer is **A: Toluene**.

### Final Answer:
The compound that possesses the `C-H` bonds with the lowest bond dissociation energy is **Toluene (A)**.