(a) Put the red litmus paper turn by turn in each of the three test tubes. The solution which turns the red litmus paper to blue will be a basic solution. Here, the blue litmus paper formed can now be used to test the acidic solution.
(b) Put this blue litmus paper in the remaining two test tubes, one by one. The solution which turns the blue litmus paper to red will be the acidic solution.
(c) The solution which has no effect on any litmus paper will be neutral and hence, it will be distilled water.
