Question

The IUPAC name of glyoxal is:

• A. 1,2-ethanedione
• B. ethane-1,2-dione
• C. ethane-1,2-dial
• D. Ethano-1,2-dial

Hint:

When naming compounds with two carbonyl groups, use "dione" and specify the positions of the carbonyl groups on the parent chain.

Answer 1

The Correct Option is B

Understanding Glyoxal:
Glyoxal is the simplest dialdehyde, with the molecular formula OHC–CHO.
It consists of a two-carbon chain with an aldehyde group (–CHO) attached to each carbon.

IUPAC Naming Rules Applied:
  1. The parent chain contains 2 carbon atoms → "ethane".
  2. Two aldehyde groups are present → use the suffix “dial”.
  3. When two identical functional groups are present on different carbon atoms, we use the locants to indicate their positions (though for aldehydes, position numbers are often omitted because –CHO is always at the terminal positions).

Therefore:
The correct IUPAC name of glyoxal is ethane-1,2-dial.

Final Answer: Option 3: ethane-1,2-dial