(a) What is a universal indicator? For what purpose is it used?

(b) How does a universal indicator work?

(a) The universal indication is a combination of several indicators that give different colours at different pH levels, indicating how acidic or basic the solution is. The scale ranges from 0 to 14 points.

(b) The universal indication is a pH indicator that changes colour when a drop of acid or base is added. Depending on the composition of the solution, it exhibits a variety of colour variations.