Question

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

Answer 1

Take three small pieces of red litmus paper. Put one drop each of the given solutions on these litmus papers. The liquid which turns red litmus into blue is a basic solution.

Divide the blue litmus paper so formed into two parts. Put one drop each of the other two liquids separately on these two pieces of litmus paper; The solution which turns blue litmus paper red is acidic solution. The solution which does not affect the colour of litmus paper is water.