What is the IUPAC name of Oxalic acid?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Ethanedioic Acid
Dicarboxylic acids, \( \ce{HOOC-(CH2)} \)n–COOH, are named in the IUPAC system by counting all the carbon atoms, including both COOH carbons, and adding the ending -dioic acid to the alkane name.
Oxalic acid, \( \ce{HOOC-COOH} \), has just two carbon atoms, both in COOH groups, so its IUPAC name is ethanedioic acid.
NCERT (2026-27 edition):
Nomenclature
Table 8.3 Names and Structures of Some Carboxylic Acids (rows)
| Structure | Common name | IUPAC name |
|---|---|---|
| HOOC–COOH | Oxalic acid | Ethanedioic acid |
| HOOC–CH2–COOH | Malonic acid | Propanedioic acid |
| HOOC–(CH2)2–COOH | Succinic acid | Butanedioic acid |
| HOOC–(CH2)3–COOH | Glutaric acid | Pentanedioic acid |
| HOOC–(CH2)4–COOH | Adipic acid | Hexanedioic acid |