Question

How do we know whether the chemical is an acid or a base?

Answer 1

by using Litmus Paper
1.when Litmus Paper become red it is acidic.
2. when Litmus Paper become blue it is basic.
thank you mate

Answer 2

We can know that the chemical given is an acid or base by conducting a litmus test. Or, as an alternative we can mix some of the given chemical in water. If the solution liberates H+ ion then the chemical is an acid and if the solution liberates OH- ions then the chemical is a base.

Hope this helps you!