Chapter 8, Problem 27Q

Classify the following aqueous solutions as acidic, neutral, or basic.

1. a. HI(aq)
2. b. NaCl(aq)
3. c. NH₄OH(aq)
4. d. [H⁺] = 1 x 10⁻⁸ M
5. e. [OH⁻] = 1 × 10⁻² M
6. f. [H⁺] = 5 × 10⁻⁷ M
7. g. [OH⁻] = 1 × 10¹² M

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

For neutral solution, the concentration of $H^{+}$ and $O{H}^{-}$ ions in the solution is same.

For acidic solution, the concentration of $H^{+}$ is larger than the concentration of $O{H}^{-}$ ions in the solution.

For basic solution, the concentration of $H^{+}$ is smaller than the concentration of $O{H}^{-}$ ions in the solution.

Explanation of Solution

$HI$ readily gives ${\text{H}}^{\text{+}}\text{ ion}$. Hence, the aqueous solution contains higher concentration of ${\text{H}}^{\text{+}}\text{ ions}$. Therefore, $HI$ is acidic.

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

For neutral solution, the concentration of $H^{+}$ and $O{H}^{-}$ ions in the solution is same.

For acidic solution, the concentration of $H^{+}$ is larger than the concentration of $O{H}^{-}$ ions in the solution.

For basic solution, the concentration of $H^{+}$ is smaller than the concentration of $O{H}^{-}$ ions in the solution.

Explanation of Solution

$\text{NaCl}$ is a salt that is formed by the neutralization of acid and base. Hence, the aqueous solution contains equal concentration of ${\text{H}}^{\text{+}}{\text{ and OH}}^{-}\text{ ions}$. Therefore, $\text{NaCl}$ is neutral.

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

For neutral solution, the concentration of $H^{+}$ and $O{H}^{-}$ ions in the solution is same.

For acidic solution, the concentration of $H^{+}$ is larger than the concentration of $O{H}^{-}$ ions in the solution.

For basic solution, the concentration of $H^{+}$ is smaller than the concentration of $O{H}^{-}$ ions in the solution.

Explanation of Solution

$N{H}_{4}OH$ readily gives ${\text{OH}}^{-}\text{ ion}$. Hence, the aqueous solution contains higher concentration of ${\text{OH}}^{-}\text{ ion}$. Therefore, $N{H}_{4}OH$ is basic.

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

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

$pOH$ of a solution is the negative logarithm of the molar concentration of hydroxide ion concentration.

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

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. For neutral solution, $\text{pH}$ is $7$.

As $\text{pOH}$ and $\text{pH}$ are opposite scale, the total of both has to be equal to 14.

  $\text{pOH}+\text{ pH =}\text{14}$

Explanation of Solution

Given that ${\text{[H}}^{\text{+}}\text{] = 1}\times {\text{10}}^{-8}\text{ M}$

pH of the solution is calculated as given,

  $\begin{array}{c}\text{pH}\text{=}-\text{log}\left[{\text{H}}^{\text{+}}\right]\\ \\ =-\text{log}\left(\text{1}\times {\text{10}}^{-8}\text{ M}\right)\\ \\ =\text{ 8}\\ \\ \text{pH}>\text{ 7}\end{array}$

pH of the aqueous solution is greater than 7. Therefore, the aqueous solution is basic.

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

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

$pOH$ of a solution is the negative logarithm of the molar concentration of hydroxide ion concentration.

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

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. For neutral solution, $\text{pH}$ is $7$.

As $\text{pOH}$ and $\text{pH}$ are opposite scale, the total of both has to be equal to 14.

  $\text{pOH}+\text{ pH =}\text{14}$

Explanation of Solution

Given that ${\text{[OH}}^{-}\text{] = 1}\times {\text{10}}^{-2}\text{ M}$

pH of the solution is calculated as given,

  $\begin{array}{c}\text{pOH}\text{=}-\text{log}\left[\text{OH}\right]\\ \\ =-\text{log}\left(\text{1}\times {\text{10}}^{-2}\text{ M}\right)\\ \\ =\text{ 2}\\ \\ pH=\text{ 14}-2\text{ = 12}\\ \\ \text{pH}>\text{ 7}\end{array}$

pH of the aqueous solution is greater than 7. Therefore, the aqueous solution is basic.

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

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

$pOH$ of a solution is the negative logarithm of the molar concentration of hydroxide ion concentration.

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

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. For neutral solution, $\text{pH}$ is $7$.

As $\text{pOH}$ and $\text{pH}$ are opposite scale, the total of both has to be equal to 14.

  $\text{pOH}+\text{ pH =}\text{14}$

Explanation of Solution

Given that ${\text{[H}}^{\text{+}}\text{] = 5}\times {\text{10}}^{-7}\text{ M}$

pH of the solution is calculated as given,

  $\begin{array}{c}\text{pH}\text{=}-\text{log}\left[{\text{H}}^{\text{+}}\right]\\ \\ =-\text{log}\left(\text{5}\times {\text{10}}^{-7}\text{ M}\right)\\ \\ =\text{ 6}\text{.3}\\ \\ \text{pH}<\text{ 7}\end{array}$

pH of the aqueous solution is less than 7. Therefore, the aqueous solution is acidic.

Interpretation Introduction

Interpretation:

Given aqueous solution has to be classified as acidic, neutral, or basic.

Concept introduction:

The $\text{pH}$ of a solution is a figure that expresses the acidity or the alkalinity of a given solution. pH is the concentration of hydrogen ion is measured using $\text{pH}$ scale. The acidity of aqueous solution is expressed by $\text{pH}$ scale.

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

$pOH$ of a solution is the negative logarithm of the molar concentration of hydroxide ion concentration.

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

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. For neutral solution, $\text{pH}$ is $7$.

As $\text{pOH}$ and $\text{pH}$ are opposite scale, the total of both has to be equal to 14.

  $\text{pOH}+\text{ pH =}\text{14}$

Explanation of Solution

Given that ${\text{[OH}}^{-}\text{] = 1}\times {\text{10}}^{-12}\text{ M}$

pH of the solution is calculated as given,

  $\begin{array}{c}\text{pOH}\text{=}-\text{log}\left[\text{OH}\right]\\ \\ =-\text{log}\left(\text{1}\times {\text{10}}^{-12}\text{ M}\right)\\ \\ =\text{ 12}\\ \\ pH=\text{ 14}-12\text{ = 2}\\ \\ \text{pH}<\text{ 7}\end{array}$

pH of the aqueous solution is less than 7. Therefore, the aqueous solution is acidic.