What is the correct IUPAC name for the compound CH2=CH−CH2−CH2OH?

The statement in the image is incorrect regarding the name "4-Buten-1-ol".

Here's the correction and explanation:

1. Identify the functional groups and determine priority:
The compound is $\text{CH}_2=\text{CH}-\text{CH}_2-\text{CH}_2\text{OH}$.
It contains two functional groups:

• A hydroxyl group ($\text{-OH}$), which makes it an alcohol.
• A carbon-carbon double bond ($\text{C}=\text{C}$), which makes it an alkene. According to IUPAC rules, the hydroxyl group ($\text{-OH}$) has higher priority than the double bond.

2. Number the carbon chain:
The carbon chain must be numbered such that the highest priority functional group (the hydroxyl group) receives the lowest possible number.

$$\overset{4}{\text{CH}_2}=\overset{3}{\text{CH}}-\overset{2}{\text{CH}_2}-\overset{1}{\text{CH}_2}\text{OH}$$

• The hydroxyl group is on carbon 1.
• The double bond starts at carbon 3 (between carbon 3 and carbon 4).

3. Construct the IUPAC name:

• The parent chain has 4 carbons, so the base name is "but-".
• The double bond is at position 3, so it's "but-3-en-".
• The alcohol group is at position 1, so it's "-1-ol".

Combining these, the correct IUPAC name is But-3-en-1-ol.

Conclusion:
The image correctly identifies that "1-Buten-4-ol" is incorrect because the alcohol group must have the lowest possible number. However, the name "4-Buten-1-ol" is also incorrect because the double bond is at position 3, not 4. The position of a double bond is indicated by the lower-numbered carbon atom involved in the bond.

The correct IUPAC name for $\text{CH}_2=\text{CH}-\text{CH}_2-\text{CH}_2\text{OH}$ is $\boxed{\text{But-3-en-1-ol}}$.