Give the names of the following when these are not the part of the parent chain :
`CH_(2)=, CH_(3)CH=, CH_(2)=CH-, CH_(2)=CH-CH_(2)-`

Explanation

To name the given groups when they are not part of the parent chain, we can follow these steps:

1. **Identify the first structure: CH₂=**
- This structure contains a double bond between two carbon atoms. When this group is not part of the main carbon chain, it is referred to as a **methylene group**.

2. **Identify the second structure: CH₃CH=**
- This structure consists of two carbon atoms, with a double bond between them. When this group is not part of the parent chain, it is called a **methylene group** (from the first carbon) and an **ethyl group** (from the second carbon). However, when specifically referring to the group as a substituent, it is known as **vinyl group**.

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