what is pH paper
pH paper is a pH indicator which are used to determine whether a solution is acidic or basic. It is a small strip of paper which contains universal indicator embedded in its pores. The following figure illustrates the various colours of the paper at different pH values.
When we put a drop of an acidic or basic solution on the pH paper, its colour changes. We can match the colour of the paper with the above colours and determine the nature of solution and hence its pH.