Chapter 17, Problem 17.25QP

Interpretation Introduction

Interpretation:

The working of an acid-base indicator in a titration 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 $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution.
• If the value of $\text{pH}$ is less than $7$, then the solution is acidic whereas if the value of $\text{pH}$ is greater than $7$, then the solution is basic.
• $\text{pH}$ is defined as the negative base-10 logarithm of the hydrogen or hydronium ion concentration.

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

Titration:

• It 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.
• 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.
• The total number of moles of standard solution (titrant) is equal to the number of moles of an unknown solution (analyte) at the equivalence point.