 So another group is the carboxyl group and that's when we have a carbon with a double-bonded oxygen and a hydroxyl group attached to it. So we will look at acetic acid which is a good example of this family. You see we have our carbon that has the hydroxyl group attached to it and also a double-bonded oxygen attached to it. So we have two carbons, the second carbon has three hydrogen. So this is just an example of the carboxyl group.