Chapter 15, Problem 21PE

(a)

Interpretation Introduction

Interpretation:

The value of $\left[{\text{H}}^{+}\right]$ when $\text{pH}$ of black coffee is 5.0 has to be calculated.

Concept Introduction:

Acidity strength is quantified by the magnitude of a parameter called $\text{pH}$. The strong acids tend to lower values of $\text{pH}$. This is since $\text{pH}$ represents negative logarithm of concentration of ${\text{H}}^{+}$ ion. So higher the concentration of ${\text{H}}^{+}$ ion lower will be $\text{pH}$.

The expression to evaluate $\text{pH}$ is as follows:

  $\text{pH}=-\log \left[{\text{H}}^{+}\right]$

Here,

$\left[{\text{H}}^{+}\right]$ denotes concentration of ${\text{H}}^{+}$ ions.

(b)

Interpretation Introduction

Interpretation:

The value of $\left[{\text{H}}^{+}\right]$ when $\text{pH}$ of black tea is 6.8 has to be calculated.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

The value of $\left[{\text{H}}^{+}\right]$ when $\text{pH}$ of green tea is 7.9 has to be calculated.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

The value of $\left[{\text{H}}^{+}\right]$ when $\text{pH}$ of laundry detergent is 9.7 has to be calculated.

Concept Introduction:

Refer to part (a).