Chapter 23, Problem 3STP

Interpretation Introduction

Interpretation:

The chemical indicator which is most effective in identifying the end point of the titration needs to be determined using the graph.

Concept introduction:

An indicator shows color change when comes in contact with an acid or an alkali solution. Some indicators are methyl orange, phenolphthalein, thymol blue etc.

Answer to Problem 3STP

Option D is the correct option.

Explanation of Solution

Given table,

From the graph, equivalence point lies in a pH range of 6-8 on the graph. So, we must use an indicator that would be effective within this range.

Given the pH range is 6.0-7.6 for bromothymol blue which is within the pH range of 6-8 according to the graph. Therefore, bromothymol bluewould be most effective in identifying the end point of the titration.

Conclusion

Methyl orange, phenolphthalein, and thymol blue does not have pH range within 6-8. Therefore, option A, B and C are incorrect.