Question

If you are given only red litmus paper ,how will you identify the contents of each test tube.

Answer 1

Hint: Litmus paper are used to identify whether a solution given in the test tube is acidic or basic according to the colour changes occurred in the litmus paper .Litmus papers are used to predict the pH range of a given solution.

Complete step by step answer:
As in the question we are given a red litmus paper. According to the concept a blue litmus paper turns to red colour when tested with an acidic solution and a red litmus paper turns to blue colour when tested with a basic (alkaline) solution . So when we will test an acidic solution given in the test tube it will not induce a change in the red litmus paper. But if the red litmus is tested with a basic solution of the test tube , the red litmus paper will turn into blue colour litmus. By this experiment we can easily identify and distinguish between acidic and basic solutions.
Additional Information: The raw materials used to make litmus paper are wood cellulose, lichens and adjacent compounds . A litmus paper should be free of contaminants so that we can observe the colour changes( pH) of the solution.

Note:
An acid is a substance which is capable of donating a proton(hydrogen ion). A base is a substance which is capable of donating a hydroxide ion. The pH range of an acid is less than 7. The pH range of a base is greater than 7 and less 14. A solution with pH 7 is said to be neutral in room temperature (298K).