Question

You have been provided with three test-tubes. 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

Three test tubes containing distilled water, an acidic solution, and a basic solution, respectively, and a blue litmus paper.

Procedure to identify the contents:

1. Identify the Acid: Dip the blue litmus paper into each of the three test tubes, one by one. The test tube that turns the blue litmus paper red contains the acidic solution.
2. Identify the Base: Take this newly formed red litmus paper and dip it into the remaining two test tubes. The test tube that turns the red litmus paper back to blue contains the basic solution.
3. Identify the Distilled Water: The last remaining test tube, which shows no colour change with either litmus paper, contains distilled water (neutral).