Question

What is the IUPAC name for the compound \( CH_3 - CH(OH) - CH_2 - CHO \)?

• A. 3-hydroxybutanal
• B. 2-hydroxybutanal
• C. 4-hydroxybutanal
• D. 1-hydroxybutanal

Hint:

In compounds containing both \( -CHO \) and \( -OH \), the aldehyde group has higher priority and determines the suffix of the compound name.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The goal is to name an organic compound containing both an alcohol (\( -OH \)) and an aldehyde (\( -CHO \)) group using IUPAC rules.
Step 2: Key Formula or Approach:
1. Identify the principal functional group based on priority: Aldehyde \(>\) Alcohol.
2. Number the longest carbon chain starting from the aldehyde carbon (\( C1 \)).
3. Name the \( -OH \) group as a substituent (hydroxy).
Step 3: Detailed Explanation:
The carbon chain has 4 carbons: \( CH_3 - CH(OH) - CH_2 - CHO \).
Numbering:
C1: \( CHO \)
C2: \( CH_2 \)
C3: \( CH \) (attached to OH)
C4: \( CH_3 \)
The parent alkane for 4 carbons is butane. Since it is an aldehyde, it is "butanal".
The hydroxy group is at position 3.
Thus, the name is 3-hydroxybutanal.
Step 4: Final Answer:
The IUPAC name is 3-hydroxybutanal.