Question

all alkalis are bases but all bases are not alkalis why

Answer 1

because alkalis are bases that can dissolve in liquids but all bases cannot be alkalis because some of them does not dissolve in water

Answer 2

hey friend

water soluble bases are known as alkalis. 

 examples of alkalis=> sodium                                                                                     hydroxide, potassium hydroxide etc.

example of insoluble bases=> copper oxide.


so, all the alkalis would be bases as they are the one which get dissolved in water.

all the bases won't be alkalis as some of them would not be able to get dissolved in water.