The IUPAC name of `CH_2 = CH - CH =CH_2` is

Options

A. Butane
B. But-1, 3-diene
C. Butane-1, 3-diene
D. none of these

Explanation

To determine the IUPAC name of the compound `CH₂=CH-CH=CH₂`, we will follow the systematic steps for naming organic compounds according to IUPAC rules.

### Step-by-Step Solution:

1. **Identify the Longest Carbon Chain**:
- The first step is to identify the longest continuous carbon chain in the molecule. In this case, the compound has 4 carbon atoms connected in a straight chain.
- The longest chain is: `CH₂=CH-CH=CH₂`.

2. **Number the Carbon Atoms**:
- Next, we need to number the carbon atoms in the longest chain. We can start numbering from either end since the double bonds are symmetrically placed.
- If we number from the left:
- Carbon 1: `CH₂`
- Carbon 2: `CH`
- Carbon 3: `CH`
- Carbon 4: `CH₂`
- The numbering gives us the positions of the double bonds.

3. **Identify the Position of Double Bonds**:
- From our numbering, we can see that there are double bonds between Carbon 1 and Carbon 2, and between Carbon 3 and Carbon 4.
- Therefore, the double bonds are located at positions 1 and 3.

4. **Determine the Base Name**:
- Since there are 4 carbon atoms in the longest chain, the base name will be derived from "butane," which corresponds to 4 carbon atoms. However, since we have double bonds, we will use "butene" as the base name.

5. **Indicate the Number of Double Bonds**:
- There are two double bonds in the compound. In IUPAC nomenclature, we use the prefix "di" to indicate the presence of two double bonds.

6. **Combine the Information**:
- The final name combines the base name, the positions of the double bonds, and the indication of multiple double bonds. Thus, we write it as:
- **1,3-butadiene**.

### Final Answer:
The IUPAC name of `CH₂=CH-CH=CH₂` is **1,3-butadiene**.

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