What is the IUPAC name of Oxalic acid?

Ethanedioic Acid

The correct answer is Option (3) → Ethanedioic Acid

Ethanedioic Acid is the correct IUPAC name for oxalic acid.

Oxalic acid has the structure HOOC-COOH, a dicarboxylic acid with two carbon atoms in the chain (both carbons are carbonyl carbons). According to IUPAC nomenclature for dicarboxylic acids, it is named as alkanedioic acid, where "alkane" is derived from the longest carbon chain including the carboxyl carbons.

• Ethane (2 carbons) → Ethanedioic acid.

Why the other options are incorrect:

• Butanedioic Acid: This is succinic acid (HOOC-CH₂-CH₂-COOH, 4 carbons).
• Propanedioic Acid: This is malonic acid (HOOC-CH₂-COOH, 3 carbons).
• Hexanedioic Acid: This is adipic acid (HOOC-(CH₂)₄-COOH, 6 carbons).