Acidic hydrogen atoms

Just because a molecule contains hydrogen atoms it won't necessarily be an acid. It depends how readily these hydrogen atoms will ionize and be released from the molecule. In some cases they are just too well bound to the rest of the molecule to be acidic.

We meet this most commonly with the organic acids. The carboxylic acids contain the COOH group, and it is this which provides the acidic hydrogen. For reasons which we shall see elsewhere, this group ionizes relatively easily. However, these acids also have hydrogen atoms attached to the carbon skeleton. These atoms are well attached and do not confer any acidity on the molecule. We saw in the alcohols section that the OH hydrogen in the alcohols is also well bound, and consequently the alcohols are neutral.