I will put red litmus paper in all the test tubes.
Acid turns blue litmus red so we will be able to identify acid.
Then put that red litmus paper in remaining two solutions .
Basic solution will turn red litmus blue.
The last remaining solution will be distilled water.
In this way,we can identify all of them.

Identifying the Contents of Each Test Tube using Blue Litmus Paper

To identify the contents of each test tube containing distilled water, an acid, and a base solution using only blue litmus paper, we can perform the following steps:

1. Label the Test Tubes
Start by labeling each test tube with a number or letter to keep track of them. Let's assume we have three test tubes labeled as Test Tube 1 (distilled water), Test Tube 2 (acid), and Test Tube 3 (base solution).

2. Dip the Blue Litmus Paper in Test Tube 1
Take a strip of blue litmus paper and dip it into Test Tube 1 containing distilled water. Observe any changes in the litmus paper's color. If the blue litmus paper remains blue, it indicates that the solution in Test Tube 1 is neutral since distilled water is neutral.

3. Dip the Blue Litmus Paper in Test Tube 2
Next, dip the same strip of blue litmus paper into Test Tube 2 containing the acid solution. Again, observe any changes in the color of the litmus paper. If the blue litmus paper turns red, it indicates that the solution in Test Tube 2 is acidic since acids turn blue litmus paper red.

4. Dip the Blue Litmus Paper in Test Tube 3
Afterward, dip the blue litmus paper into Test Tube 3 containing the base solution. Observe any changes in the color of the litmus paper. If the blue litmus paper remains blue or turns purple, it indicates that the solution in Test Tube 3 is basic/alkaline since bases do not affect blue litmus paper.

5. Interpret the Results
Based on the observations, we can interpret the contents of each test tube as follows:

- Test Tube 1: If the blue litmus paper remained blue, it confirms that the contents of Test Tube 1 are distilled water, which is neutral.
- Test Tube 2: If the blue litmus paper turned red, it confirms that the contents of Test Tube 2 are an acid.
- Test Tube 3: If the blue litmus paper remained blue or turned purple, it confirms that the contents of Test Tube 3 are a base/alkaline solution.

By following the above steps and interpreting the results, we can successfully identify the contents of each test tube containing distilled water, an acid, and a base solution using only blue litmus paper.