Difference between Alkali and Base: Overview, Questions, Preparation

What is an alkali?

Alkali is a salt of an alkaline metal or an alkaline earth metal. They are soluble in water and have a pH of above 7.

They are a subset of bases. Thus we can say that all alkali are bases. But, all bases are not alkali.

Alkalis can be classified as strong or weak based on the ionic salt present. They are commonly used as a cleaning agent and to manufacture detergents and soaps.

What is a base?

A base is a slippery substance that accepts hydrogen ions from other compounds or elements. There are three ways to define and categorize a base. They are as follows:

• Arrhenius concept:

According to the Arrhenius concept, a base is a substance that releases hydroxide ions (OH-) when dissolved in water. It is one of the simplest definitions of a base to date. However, various bases do not release hydroxide ions in water. Hence, the definition is true for some bases and not all.

• Bronsted Lowry concept

According to the Bronsted Lowry concept, any substance or compound that can accept a hydrogen ion (H+) will be termed as a base. This definition also held for some of the bases and not all. There are also compounds like H2O that accept hydrogen ions (to form H3O+) but are not a base.

• Lewis concept

According to the Lewis concept, any compound that can donate a lone pair of electrons can be termed as a base. This definition proved to be the best way to categorize a base as it covers all the aspects.