Chapter U6, Problem 6RE

Interpretation Introduction

Interpretation:

The function of acid base indicator with equilibrium needs to be identified.

Concept introduction:

When the change in concentrations of reactants and products is same and their concentration become constant then the system is said to be in equilibrium.

Answer to Problem 6RE

An acid base indicator indicates the alterations in the equilibrium of reaction.

Explanation of Solution

The substances which respond to an alteration in the hydrogen ion concentration of a solution are known as acid-base indicators. Through a color change, one can recognize this change most often.

Whether a solution is acidic or basic, one can identify by a numeric scale known as pH. A pH value smaller than 7 is acidic, whereas pH values higher than 7 is basic. A pH equal to 7 is neutral.

When a change in equilibrium to the weak acid and its conjugate base takes place, the change in pH takes place and when the hydrogen ion concentration changes, a shift in equilibrium occurs takes place.

This shift in equilibrium due to change in pH can be indicated by acid-base indicators by change in color of the solution.

For example: For a weak acid indicator, the color for an acid and its conjugate base will be different. Similarly, if indicator is a weak base, different color will be displayed by the base and its conjugate acid.