Question

All alkalis are bases but all bases are not alkalis. Why?

Answer 1

A base is any substance that neutralizes the acid. It may or may not be soluble in water. Those bases which are soluble in water are called alkalis. Thus, an alkali is a water-soluble base. For example sodium hydroxide, potassium hydroxide, etc.
Therefore, it is said that all alkalis are bases but all bases are not alkalis.