The central bond in 1,3 butadiene is _______ than that of n-butane .

Explanation

To determine the nature of the central bond in 1,3-butadiene compared to that of n-butane, we can follow these steps:

### Step 1: Draw the Structures
1. **1,3-butadiene** has the following structure:
- It consists of four carbon atoms with double bonds between the first and second, and the third and fourth carbon atoms.
- The structure can be represented as:
```
H2C=CH-CH=CH2
```

2. **n-butane** has the following structure:
- It consists of four carbon atoms connected by single bonds.
- The structure can be represented as:
```
CH3-CH2-CH2-CH3
```

### Step 2: Identify the Central Bond
- In **1,3-butadiene**, the central bond is the bond between the second and third carbon atoms (C2-C3).
- In **n-butane**, the central bond is the bond between the second and third carbon atoms (C2-C3) as well.

### Step 3: Determine Hybridization
- For **1,3-butadiene**:
- The carbon atoms involved in the central bond (C2 and C3) are each sp² hybridized because they are involved in a double bond (one sigma bond and one pi bond).

- For **n-butane**:
- The carbon atoms involved in the central bond (C2 and C3) are each sp³ hybridized because they are involved only in single bonds (sigma bonds).

### Step 4: Compare Bond Lengths
- The bond length is influenced by the type of hybridization:
- **sp** hybridized bonds are the shortest.
- **sp²** hybridized bonds are longer than sp but shorter than sp³.
- **sp³** hybridized bonds are the longest.

- Therefore, the bond length order is:
- sp < sp² < sp³

### Conclusion
- Since the central bond in 1,3-butadiene (sp²) is shorter than the central bond in n-butane (sp³), we conclude that the central bond in 1,3-butadiene is **shorter** than that of n-butane.

### Final Answer
The central bond in 1,3-butadiene is **shorter** than that of n-butane.

---