<p>Acid strength is based on the tendency of an acid to dissociate into a hydrogen ion and an anion. A strong acids are able to completely dissociate while weak acids can't. The easier it is for an acid to dissociate, the more acidic it will be. </p><p>So on the periodic table, the least electronegative element is iodine. Thus the strongest acid will be HI which is hydrogen iodide</p><p>Base strength is also the tendency of a base to separate into a hydroxyl ion and a cation. Strong bases can do this completely and weak bases cannot.</p><p>As with acids, the strongest base will be a combination of the hydroxyl ion and the least electropositive element. And it was LiO which is lithium mono oxide. But recent studies and research created something called a superbase.</p><p>The super base is called Ortho-diethynylbenzene dianion. It was synthesized in Australia and has taken the place of LiO as the strongest base</p>