Question

How can we identify an acid or base?

Answer 1

using litmus paper .when red litmus changes into blue it is base when red litmus remains red it is acid.

Answer 2

acids are sour in taste whereas bases are bitter in taste.
but some acids and bases are dangerous and we cannot even touch them.
a  special substance,called indicator is used for identifying whether a substance is acid or base. it changes its color in acids and base.
example, litmus paper turn red in acids and blue in bases.