Give IUPAC name of the following :
`CH_(2) = CHCHO`

Explanation

To determine the IUPAC name of the compound `CH₂=CHCHO`, we can follow these steps:

### Step 1: Identify the longest carbon chain
The given compound has three carbon atoms:
- The first carbon is part of the double bond (CH₂).
- The second carbon is also part of the double bond (CH).
- The third carbon is part of the aldehyde group (CHO).

### Step 2: Determine the functional group
The functional group present in the compound is an aldehyde (–CHO). Aldehydes are characterized by the presence of a carbonyl group (C=O) at the end of the carbon chain.

### Step 3: Number the carbon chain
When numbering the carbon chain, we start from the end closest to the functional group (aldehyde) to ensure it gets the lowest possible number:
- The carbon chain is numbered as follows:
1. CHO (1st carbon)
2. CH (2nd carbon, part of the double bond)
3. CH₂ (3rd carbon)

### Step 4: Identify the position of the double bond
In this case, the double bond is located between the 2nd and 3rd carbon atoms.

### Step 5: Combine the names and assign suffixes
- The base name for a three-carbon chain is "prop".
- Since there is a double bond starting at the 2nd carbon, we use the prefix "2" and the suffix "ene" to indicate the presence of the double bond.
- The aldehyde functional group will be indicated with the suffix "al".

### Step 6: Write the complete IUPAC name
Combining all the information:
- The compound has three carbons (prop).
- The double bond is at position 2 (2-ene).
- The aldehyde group is present (1-al).

Thus, the IUPAC name of the compound `CH₂=CHCHO` is **prop-2-enal**.

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