Which one of the following has inductive, mesomeric and hyperconjugation effect ?

Options

A. `CH_(3)Cl`
B. `CH_(3)-CH=CH_(2)`
C. `CH_(3)CH=CH-underset(O)underset(||)C-CH_(3)`
D. `CH_(2)=CH-CH=CH_(2)`

Answer

To determine which compound exhibits inductive, mesomeric, and hyperconjugation effects, we need to analyze each option based on the definitions of these effects.

### Step-by-Step Solution:

1. **Understanding Inductive Effect**:
- The inductive effect is the polarization of sigma bonds due to the electronegativity of atoms or groups attached to them. Electronegative atoms withdraw electron density from the sigma bond, creating a partial positive charge on the carbon atom.

2. **Understanding Mesomeric Effect**:
- The mesomeric effect (or resonance effect) involves the delocalization of electrons between pi bonds and lone pairs on adjacent atoms. It can stabilize the molecule by allowing charge distribution.

3. **Understanding Hyperconjugation**:
- Hyperconjugation refers to the interaction of the electrons in a sigma bond (like C-H or C-C) with an adjacent empty or partially filled p-orbital or pi bond, leading to increased stability.

4. **Analyzing the Options**:
- **Option A: CH3Cl**
- Chlorine is electronegative, so it shows an inductive effect (−I). However, it does not exhibit mesomeric or hyperconjugation effects. **(Incorrect)**

- **Option B: CH3-CH=CH2**
- This compound can show hyperconjugation due to the presence of the double bond and adjacent hydrogen atoms. However, there are no electronegative atoms for the inductive effect and no resonance structures for mesomeric effect. **(Incorrect)**

- **Option C: CH3-CH=CH-CO-CH3**
- In this compound:
- The oxygen atom is electronegative, which contributes to the inductive effect (−I).
- The double bond allows for resonance structures, exhibiting the mesomeric effect.
- The presence of adjacent hydrogen atoms allows for hyperconjugation.
- Therefore, this compound shows all three effects. **(Correct)**

- **Option D: CH2=CH-CH=CH2**
- This compound primarily shows mesomeric effects due to the presence of double bonds but lacks electronegative atoms for inductive effects and does not have adjacent hydrogen atoms for hyperconjugation. **(Incorrect)**

5. **Conclusion**:
- The correct answer is **Option C: CH3-CH=CH-CO-CH3**, as it exhibits inductive, mesomeric, and hyperconjugation effects.