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? - Science

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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?

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Solution 1

If the colour of red litmus does not change then it is acid.

If the colour of red litmus changes to blue then it is base.

If there is slight change in the colour of red litmus (such as purple) then it is distilled water.

Solution 2

Using the red litmus paper, we can identify the content in each of the test tube. This can be done by noticing the color change of the red litmus paper.

  • If the red litmus paper changes to blue color it means that, the solution is a basic solution.
  • If we put the changed litmus paper into another solution to see if it changes to red again. If it does change that means that solution will be an acidic solution.
  • The solution that has no change in any of the litmus paper will be the neutral solution therefore that will be the distilled water.
Concept: Acids
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Chapter 2: Acids, Bases and Salts - Intext Questions [Page 18]

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NCERT Science Class 10
Chapter 2 Acids, Bases and Salts
Intext Questions | Q 1 | Page 18

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