Carboxylic Acid Structure and Chemistry

Carboxylic acids are hydrocarbon derivatives containing a carboxyl (COOH) moiety. Recall that carbon has four valence electrons and therefore requires four electrons or bonds to complete its octet. Based on this valence and bonding order, carbon forms four bonds in its neutral state, and these may be four single bonds or combinations of single and multiple bonds. Oxygen has six valence electrons and therefore requires two electrons or bonds to complete its octet and these may be single or double (pi) bonds. In the carboxylic acid functional group, carbon forms a double bond to one oxygen atom forming a carbonyl moiety, a single bond to another oxygen forming a hydroxyl group. The fourth bond is to another carbon atom (or H in the case of formic acid).