What is meant by Arrhenius Concept & Lewiss Concept?
The Arrhenius acid-base concept classifies a substance as an acid if it produces hydrogen ions H(+) or hydronium ions in water. A substance is classified as a base if it produces hydroxide ions OH(-) in water. This way of defining acids and bases works well for aqueous solutions, but acid and base properties are observed in other settings also.Hence,we needed other theories.
According to this concept, an acid is a species (charged or uncharged), which can accept a pair of electrons and a base is a species (charged and uncharged), which can donate a pair of electrons towards the formation of a covalent bond. Thus, a Lewis acid is an electrophile, and a Lewis base is a nucleophile. For example, in the reaction