Chapter 19, Problem 19.40P

Interpretation Introduction

Interpretation:

The color change of an indicator takes place over a range of 2 $\text{pH}$ units, for this fact reason has to be given.

Concept Introduction:

Basis of an indicator detection:

  An indicator is a substance (mostly in liquid form) that it changes its colour based on the $\text{pH}$ values.

For an example, phenolphthalein is an acid-base indicator, and its color changes when the $\text{pH}$ of the solution is changed from acidic to basic (used in the $\text{pH}$ range of 8.3 – 10.).