The IUPAC name of the following organic compound is HOOC - COOH

Step 1: Analyze the question

The compound is HOOC-COOH. It has two carbon atoms, and each carbon is part of a carboxylic acid group (-COOH). We need its IUPAC name, not its common (trivial) name.

Step 2: Concept

• Parent chain: 2 carbons, so "eth-" (ethane).
• For a carboxylic acid, the ending "-e" of the alkane is replaced by "-oic acid".
• With two -COOH groups, we keep the "e" and use "-dioic acid": ethanedioic acid.
• The carboxyl carbons are always carbon 1 of the chain, so here they are C1 and C2.

Step 3: Check the options

• A. ethan-1,2-dioc acid: This is the closest to the correct name, ethane-1,2-dioic acid (ethanedioic acid). The spelling "dioc" is a typo for "dioic", but it is the only option with the right parent chain and two acid groups.
• B. ethanoic acid: This is CH₃COOH, with only one acid group. Wrong.
• C. oxalic acid: This is the correct common (trivial) name for HOOC-COOH, but not the IUPAC name. Wrong for this question.
• D. propan-1,2-dioic acid: This has 3 carbons. Wrong.

Step 4: Answer

The IUPAC name is ethane-1,2-dioic acid (ethanedioic acid), which matches option A.

Tip: Whenever a question says "IUPAC name", avoid common names like oxalic acid, formic acid, or acetic acid. Count the carbons, then add the correct suffix: "-oic acid" for one acid group and "-dioic acid" for two. Remember the pair: oxalic acid is the common name, ethanedioic acid is the IUPAC name.