Vitamin C (ascorbic acid) is not formed from a carboxylic acid and an alcohol. It's a lactone, which means it's a cyclic ester.

Here's the breakdown:

* Lactones are cyclic esters formed by the intramolecular reaction of a hydroxy group and a carboxyl group within the same molecule.

* Vitamin C has a lactone ring structure, along with a five-membered ring containing a ketone and a hydroxyl group.

So, it's not made by combining a carboxylic acid and an alcohol; it's a single molecule with a unique structure containing a lactone ring.