$A$ solution turns red litmus blue,its $pH$ is likely to be

On what basis are acids classified as strong and weak acids?

Write true or false for the following statement:
Acids that give rise to more $H^+$ ions are said to be strong acids,and acids that give less $H^+$ ions are said to be weak acids.

What happens to the $pH$ of a basic aqueous solution if the concentration of $[OH^-]$ ions increases?

If the approximate $pH$ of a solution is $7,$ what will be the colour of $pH$ paper when dipped into that solution?

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