Question

Suppose you forget to write down the contents of four test tubes. Each contains a different solution that has a different pH. What is the best way to quickly identify the contents of each test tube? a. check the ph of each solution with a ph meter b. add sodium hydroxide to each solution, then check the ph with a meter c. check the ph of each solution with thymol blue d. add hydrocholoric acid to each solution, then check the ph with a meter

Answer 1

The best way to identify the contents of each test tube is to check the pH of each solution with pH meter, i.e. option 'a'

Explanation: Here, the solutions in all the 4 test tubes have different pH. Therefore, you simply measure the pH of all the 4 solutions using pH meter to find which one is what.

In the case of adding HCl to each solution, you should add the appropriate indicator if the solution is basic in nature, which you don't know exactly.

In the case of adding NaOH to each solution, you should add the appropriate indicator if the solution is acidic in nature, which you don't know exactly.

In the case of adding thymol blue indicator, you will get to know about the range of pH (i.e. if the solution in the test tube is acidic, a pH of 1.2-2.8 and if the solution is basic, a pH of 8.0-9.6).

Hence, the option a is the best way to identify each solution.