Chapter 15, Problem 51AE

(a)

Interpretation Introduction

Interpretation:

Whether a substance that turns red litmus to blue is acidic, basic or neutral has to be determined.

Concept Introduction:

Acids are substances usually sour in taste, corrosive and turn blue litmus turns red. The bases are substances that are soapy to touch bitter and have ability to turn red litmus to blue. The neutral substances show no color change on test with litmus solution.

(b)

Interpretation Introduction

Interpretation:

Whether a substance with 6 as $\text{pH}$ is acidic, basic or neutral has to be identified.

Concept Introduction:

The 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 $\text{pOH}$ is as follows:

  $\text{pOH}=-\log \left[{\text{OH}}^{-}\right]$

Here,

$\left[{\text{OH}}^{-}\right]$ denotes concentration of ${\text{OH}}^{-}$ ions.

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

  $\text{pH}=\text{14}-\mathrm{pOH}$

(c)

Interpretation Introduction

Interpretation:

Whether a substance with $1\times {10}^{-7}\text{ M}$ as concentration of ${\text{H}}^{+}$ ion is acidic, basic or neutral has to be identified.

Concept Introduction:

The 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.

(d)

Interpretation Introduction

Interpretation:

Whether a substance that has $1\times {10}^{-8}\text{ M}$ as concentration of ${\text{OH}}^{-}$ ion is acidic, basic or neutral has to be identified.

Concept Introduction:

Refer to part (b).

(e)

Interpretation Introduction

Interpretation:

Whether a substance that turns blue litmus to red is acidic, basic or neutral has to be determined.

Concept Introduction:

Refer to part (a).

(f)

Interpretation Introduction

Interpretation:

Whether a substance with 12 as $\text{pH}$ is acidic, basic or neutral has to be identified.

Concept Introduction:

Refer to part (b).