Question

all alkalis are bases justify this statement.

Answer 1

Bases are substances that react with acids and neutralise them. They are usually metal oxides, metal hydroxides, metal carbonates or metal hydrogen carbonates. Many bases are insoluble - they do not dissolve in water.

If a base does dissolve in water, we call it an alkali.

Here are two examples:

Copper oxide is a base because it will react with acids and neutralise them, but it is not an alkali because it does not dissolve in water.

Sodium hydroxide is a base because it will react with acids and neutralise them. It's also an alkali because it dissolves in water.

Thus all alkalis are bases, but all bases except hydroxides are not alkalis.
hope it helps u

Answer 2

Bases which are soluble in water are alkalis.

All alkalis are bases as they taste bitter and feel soapy.

All alkalis are bases but all bases are not alkalis.