What is a common method for identifying the reactivity of group alkali metals?

The reactivity of alkali metals is commonly identified through displacement reactions, where a more reactive metal can displace a less reactive metal from a compound. Alkali metals, which are found in Group 1 of the periodic table, are known for their high reactivity, particularly with non-metals such as halogens or with water.

In a typical displacement reaction involving alkali metals, when they react with a less reactive metal compound, they can replace the metal in that compound because they are more reactive. This behavior can provide clear evidence of the reactivity series of metals, demonstrating how alkali metals rank in terms of their ability to displace other metals.

Other methods like electrolysis, while useful for various purposes in chemistry, do not specifically address the reactivity trends within the group of alkali metals. Filtration and evaporation are separation techniques that don't directly measure or indicate chemical reactivity. Thus, the identification of reactivity through displacement reactions aligns closely with the fundamental properties of alkali metals and their behavior in chemical reactions.