The correct IUPAC name of `CH_(2)=CHOH` is

Options

A. ethenol
B. ethanol
C. ethenal
D. ethanal

Answer

To determine the correct IUPAC name for the compound `CH₂=CHOH`, we can follow these steps:

### Step 1: Identify the Structure
The given compound can be represented as:
- CH₂=CH-OH

This indicates that we have a carbon-carbon double bond (C=C) and a hydroxyl group (-OH) attached to one of the carbons.

### Step 2: Count the Carbon Atoms
The compound contains two carbon atoms:
- The first carbon (C1) is part of the double bond and is connected to another carbon (C2) and a hydroxyl group (OH).
- The second carbon (C2) is connected to the first carbon via a double bond.

### Step 3: Determine the Longest Carbon Chain
Since there are only two carbon atoms, the longest carbon chain is simply:
- Ethene (C2H4) because it consists of two carbon atoms.

### Step 4: Identify the Functional Group
The functional group present is the hydroxyl group (-OH), which is characteristic of alcohols.

### Step 5: Assign the Locants
According to IUPAC naming conventions, we need to assign the lowest possible number to the functional group:
- The hydroxyl group is on the first carbon (C1), so we will denote it as 1-ol.

### Step 6: Combine the Name
Now we can combine the names:
- The base name for the two-carbon alkene is "ethene."
- Since the hydroxyl group takes precedence over the double bond, we name it as "ethen-1-ol."

### Final Answer
Thus, the correct IUPAC name for `CH₂=CHOH` is **ethen-1-ol**.

---