[NikoBellic909]

Hi, I have a doubt on the topic of bases and alkalis. I have learnt that a alkali is a soluble base so does that mean Sodium Oxide(Solid) is a alkali and Lithium Hydroxide(Solid) is a alkali. Or are they considered alkali when they are dissolved? For example, Sodium Oxide becomes sodium hydroxide which is alkali in aqueous form.

[mikasaur]

The former.

From Wikipedia:

An alkali is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali also can be defined as a base that dissolves in water.