Chapter 17, Problem 17.28QP

Interpretation Introduction

Interpretation:

The pink colour turns to colourless solution in titration after the equivalence point as the solution is left for some time has to be explained.

Concept introduction:

Acid-base indicator contains weak acid or base. It causes to change the colour of solution with change in $\text{pH}$ at end point.

The point at which amount of standard solution and analyte becomes equal and neutralisation happens in titration is called equivalence point.

The end point is defined as occurrence of colour change at particular point in titration.

Titration is a process where a known concentrated solution is used for determining the concentration of an unknown solution. The known concentrated solution is called the titrant, while the unknown concentrated solution is called the analyte. 

The equivalence point is a point in a titration where the amount of standard solution added is sufficient to neutralize the unknown solution completely. At this point, the total number of moles of standard solution (titrant) is equal to the number of moles of an unknown solution (analyte).

$\text{pH}$: The concentration of hydrogen ion is measured using $\text{pH}$ scale. The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution.

It is defined as the negative base-10 logarithm of the hydrogen or hydronium ion concentration.

$\text{pH}\text{=}{\text{-log[H}}_{\text{3}}{\text{O}}^{\text{+}}\text{]}$