1,3- Pentadiene and 1,-4 - pentadiene are compared with respect to their intrinsic stability and reaction with HI . The correct statement is

Options

A. 1,3 pentadiene is more stable and more reactive than 1,4- pentadiene
B. 1,3 pentadiene is less stable and less reactive than 1,4- pentadiene
C. 1,3 pentadiene is more stable and less reactive than 1,4- pentadiene
D. 1,3 pentadiene is less stable and less reactive than 1,4- pentadiene

Answer

To solve the problem comparing the intrinsic stability and reactivity of 1,3-pentadiene and 1,4-pentadiene, we can follow these steps:

### Step 1: Identify the Structures
1. **1,3-Pentadiene**: This compound has a structure where the double bonds are located at the first and third carbon atoms. The structure can be represented as:
```
H2C=CH-CH=CH-CH3
```
Here, the double bonds are conjugated.

2. **1,4-Pentadiene**: This compound has double bonds at the first and fourth carbon atoms, represented as:
```
H2C=CH-CH2-CH=CH2
```
In this case, the double bonds are isolated.

### Step 2: Analyze Stability
- **Conjugation vs. Isolation**: Conjugated systems (like 1,3-pentadiene) are generally more stable than isolated systems (like 1,4-pentadiene) due to the delocalization of π electrons across the double bonds. This delocalization lowers the overall energy of the molecule.

### Step 3: Analyze Reactivity
- **Reactivity with HI**: Conjugated alkenes tend to be more reactive than isolated alkenes because they can stabilize the transition state better during reactions such as hydrohalogenation. Therefore, 1,3-pentadiene, being conjugated, will react more readily with HI compared to 1,4-pentadiene.

### Conclusion
Based on the analysis:
- **1,3-pentadiene is more stable and more reactive than 1,4-pentadiene** due to its conjugated double bonds.

### Final Answer
The correct statement is: **1,3-pentadiene is more stable and more reactive than 1,4-pentadiene.**

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