Carboxylic Acids - Structure and Basics
The functional group that defines carboxylic acids is -COOH, which gives them their distinctive properties. When naming these compounds, you simply add the suffix -oic acid to the end (like ethanoic acid for vinegar).
If a molecule has two carboxylic acid groups, you use -dioic acid instead. Think of it as doubling up on the acidity! The general structure shows a carbon atom bonded to both a hydroxyl group and a carbonyl group .
The geometry around the carbon is particularly important - you'll find three regions of electron density creating bond angles of 120°, whilst the oxygen in the -OH group has two bonded pairs and two lone pairs, giving it a 104.5° angle.
Key Insight: The -COOH group combines two familiar functional groups (carbonyl and hydroxyl), which explains why carboxylic acids are so reactive and versatile.
