What is a universal indicator? State the purpose for which this indicator is used.

(N/A) universal indicator is a mixture of several indicators that exhibits a range of different colours over a wide range of $pH$ values.
It is used to determine the strength of an acid or a base in a solution by indicating the concentration of hydrogen ions $(H^+)$ present.
By comparing the colour produced with a standard $pH$ colour chart,one can estimate the approximate $pH$ value of the solution.