Which of the following group has the maximum hyperconjugation effect ?

Options

A. `CH_(3)-`
B. `CH_(3)CH_(2)-`
C. `(CH_(3))_(2)CH-`
D. `(CH_(3))_(3)C-`

Explanation

To determine which of the given groups has the maximum hyperconjugation effect, we need to analyze the number of alpha hydrogens present in each group. Hyperconjugation is the interaction of the electrons in a sigma bond (usually C-H or C-C) with an adjacent empty or partially filled p-orbital or a π-bond, which stabilizes the molecule.

### Step-by-Step Solution:

1. **Identify the Groups**:
Let's denote the groups as follows:
- Group A: CH3 (Methyl group)
- Group B: CH3CH2 (Ethyl group)
- Group C: CH3CH (Isopropyl group)
- Group D: CH3C (Tertiary carbon with no hydrogens)

2. **Determine the Alpha Carbons**:
- Alpha carbon is the carbon atom directly attached to the functional group or the carbon chain we are considering.
- For hyperconjugation, we focus on the hydrogen atoms attached to these alpha carbons.

3. **Count the Alpha Hydrogens**:
- **Group A (CH3)**:
- 3 alpha hydrogens (from CH3).
- **Group B (CH3CH2)**:
- 2 alpha hydrogens from CH2 and 3 from CH3 = 5 alpha hydrogens.
- **Group C (CH3CH)**:
- 1 alpha hydrogen from CH and 3 from CH3 = 4 alpha hydrogens.
- **Group D (CH3C)**:
- No alpha hydrogens (the carbon is tertiary with no hydrogen attached).

4. **Compare the Number of Alpha Hydrogens**:
- Group A: 3 alpha hydrogens
- Group B: 5 alpha hydrogens
- Group C: 4 alpha hydrogens
- Group D: 0 alpha hydrogens

5. **Conclusion**:
The group with the maximum number of alpha hydrogens is Group B (CH3CH2), which has 5 alpha hydrogens. Therefore, it exhibits the maximum hyperconjugation effect.

### Final Answer:
**Group B (CH3CH2) has the maximum hyperconjugation effect.**