Chapter 15, Problem 15.133QP

(a)

Interpretation Introduction

Interpretation:

The strength of the given strong acid $(\text{HA)}$ and weak acid $\text{(HB)}$ $pH$ should be measured under given conditions.

Concept Information:

pH definition:

The concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

The $\text{pH}$ of a solution is defined as the negative base-10 logarithm of the hydrogen or hydronium ion concentration.

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

Strong acids:

In strong acids, the ionization of acid is complete. This implies that the concentration of the hydrogen ion or hydronium ion will be equal to the initial concentration of the acid at equilibrium.

Weak acids:

In weak acids, the ionization of acid is not complete.  This implies that the concentration of the hydrogen ion or hydronium ion will not be equal to the initial concentration of the acid at equilibrium.

For strong acids the concentration of acid will be same as that of the concentration of hydrogen ions, because strong acids undergo complete ionization.

In case of weak acid, the concentration of hydrogen ion will be less than the concentration of given acid; since weak acid does not ionize completely.

(b)

Interpretation Introduction

Interpretation:

The strength of the given strong acid $(\text{HA)}$ and weak acid $\text{(HB)}$ the electrical conductance should be measured under given conditions.

Concept Information:

Electrical conductance: When voltage is applied to the electrode dipped into an electrical solution, ion of the electrolyte move and electric current flows through the electrolytic solution.

Strong acids:

In strong acids, the ionization of acid is complete.  This implies that the concentration of the hydrogen ion or hydronium ion will be equal to the initial concentration of the acid at equilibrium.

Weak acids:

In weak acids, the ionization of acid is not complete.  This implies that the concentration of the hydrogen ion or hydronium ion will not  be equal to the initial concentration of the acid at equilibrium.

For strong acids the concentration of acid will be same as that of the concentration of hydrogen ions, because strong acids undergo complete ionization.

In case of weak acid, the concentration of hydrogen ion will be less than the concentration of given acid; since weak acid does not ionize completely.

(c)

Interpretation Introduction

Interpretation:

The strength of the given strong acid $(\text{HA)}$ and weak acid $\text{(HB)}$ has to be compared based on the following conditions. The rate of hydrogen gas evolution when these solutions are combined with an active metal such as $\text{Mg}$ or $\text{Zn}$.

Concept Information:

Strong acids:

In strong acids, the ionization of acid is complete.  This implies that the concentration of the hydrogen ion or hydronium ion will be equal to the initial concentration of the acid at equilibrium.

Weak acids:

In weak acids, the ionization of acid is not complete.  This implies that the concentration of the hydrogen ion or hydronium ion will not be equal to the initial concentration of the acid at equilibrium.

For strong acids the concentration of acid will be same as that of the concentration of hydrogen ions, because strong acids undergo complete ionization.

In case of weak acid, the concentration of hydrogen ion will be less than the concentration of given acid; since weak acid does not ionize completely.