Oxidation of Ethylene Glycol to Oxalic Acid

Steps:

• Identify oxalic acid as HOOC-COOH, a two-carbon dicarboxylic acid formed by complete oxidation of a vicinal diol.
• Recognize that primary alcohols oxidize to carboxylic acids; diols with adjacent OH groups undergo cleavage under strong oxidation.
• Determine the precursor alcohol must be ethylene glycol (HO-CH₂-CH₂-OH), a two-carbon diol.
• Confirm via reaction: KMnO₄ oxidation of ethylene glycol yields oxalic acid by oxidizing both -CH₂OH to -COOH with C-C bond cleavage.

Why C is correct:

• Ethylene glycol (option C) is a 1,2-diol whose both primary alcohol groups oxidize to carboxylic acids, forming HOOC-COOH per standard organic oxidation rules.

Why the others are wrong:

• A (methanol): Oxidizes to formic acid (HCOOH), a one-carbon monoacid.
• B (ethanol): Oxidizes to acetic acid (CH₃COOH), a two-carbon monoacid.
• D (glycerol): Oxidizes to glyceric acid or tartronic acid, not oxalic acid.

Final answer: C