Acids are compounds that tend to produce hydrogen ions in water. Remember that ions are atoms that have gained or lost electrons.
Most acids also contain oxygen as part of an acid radical ion.
A radical is a combination of atoms that form part of a molecule or work as a single ion. This forms an hydroxide radical OH. 5. Bases are usually metal oxides and hydroxides. Bases that can be dissolved in water are called alkalis. You can find out what is a base and what is an acid by using an indicator or litmus paper.