Question

You have been provided with three test-bubes. One  of these test-tubes contains distilled water and the other two contain an acidic and a basic solution respectively. If you are given only blue litmus paper, how will you identify the contents of each test-tube?

Answer 1

We have been provided with three test tubes, containing distilled water, an acidic solution and a basic solution. The test tube containing distilled water will not bring about any change in the colour of the blue litmus paper. Now, when you dip the same litmus paper in the test tube containing the acidic solution, it will turn the blue colour of the litmus paper to red. The basic solution in the third test tube will have no effect on blue litmus paper but will revert back the colour of litmus paper to blue which was earlier turned red by the acidic solution.