A base that is dissolved in water produces hydroxide ions, which are also known as hydroxyl ions. A hydroxide ion has one oxygen atom and one hydrogen atom.
According to Encyclopedia Britannica, a base is any substance that, when in placed in a water solution, is slippery when touched, tastes bitter and changes the color of indicators, such as turning red litmus paper to blue. Bases also react with acid, which leads to the formation of salts and promotes certain chemical reactions, known as base catalysis. Some strong bases are sodium hydroxide, lithium hydroxide, potassium hydroxide and rubidium hydroxide. Some weak bases are ammonia, magnesium hydroxide, lime and sodium silicate. The difference between strong and weak bases is that weak bases do not completely ionize in a water solution.