The species which will not show hyperconjugation is

Options

A. `CH_3C^(+)H_2`
B. `(CH_3)_3C C^(+)H_2`
C. `CH_3CH_2C^(+)H_2`
D. `CH_3C^(+)HCH_2`

Answer

To determine which species does not show hyperconjugation, we need to analyze each option based on the presence of alpha hydrogen atoms adjacent to a positively charged carbon atom. Hyperconjugation involves the delocalization of sigma electrons from C-H bonds to an empty or partially filled p-orbital of an adjacent carbon atom.

### Step-by-Step Solution:

1. **Understanding Hyperconjugation**:
- Hyperconjugation occurs when there are alpha hydrogen atoms adjacent to a positively charged carbon atom. The sigma electrons from the C-H bond can delocalize into the empty p-orbital of the positively charged carbon.

2. **Analyzing Option 1: CH3C^+H2**:
- The structure has a positively charged carbon (C^+) with three alpha hydrogen atoms on the adjacent carbon (CH3).
- Since there are alpha hydrogens, hyperconjugation is possible.

3. **Analyzing Option 2: CH3C^+CH3**:
- The positively charged carbon (C^+) is adjacent to another carbon (C) that has no hydrogen atoms attached to it.
- Since there are no alpha hydrogen atoms, hyperconjugation is not possible. This is a strong candidate for the answer.

4. **Analyzing Option 3: CH3CH2C^+H2**:
- The positively charged carbon (C^+) has two alpha hydrogen atoms on the adjacent carbon (CH2).
- Since there are alpha hydrogens, hyperconjugation is possible.

5. **Analyzing Option 4: CH3C^+HCH3**:
- The positively charged carbon (C^+) is adjacent to two carbons, both of which have hydrogen atoms.
- There are three alpha hydrogen atoms available for delocalization, so hyperconjugation is possible.

6. **Conclusion**:
- The only species that does not show hyperconjugation is **Option 2: CH3C^+CH3** because it lacks alpha hydrogen atoms.

### Final Answer:
**Option 2: CH3C^+CH3 does not show hyperconjugation.**