Chapter 17, Problem 43E

Interpretation Introduction

(a)

Interpretation:

The solution with $\text{pH}=\text{7}$ is to be classified as strongly acidic, weakly acidic, strongly basic, weakly basic, neutral, or close to neutral.

Concept introduction:

The $\text{pH}$ scale tells about the strength of an acid and a base. It measures the concentration of the hydrogen ions. There is an inverse relationship between the $\text{pH}$ value and the concentration of the hydrogen ion. Higher the concentration of hydrogen ions, lesser the value of $\text{pH}$. There is an inverse relationship between the $\text{pOH}$ value and the concentration of the hydroxide ion. Higher the concentration of hydroxide ions, lesser the value of $\text{pOH}$.

Answer to Problem 43E

The given solution is neutral in nature.

Explanation of Solution

The $\text{pH}$ scale tells about the strength of an acid and a base. The $\text{pH}$ range on $\text{pH}$ scale is from $0$ to $14$. The acidity decreases from $0$ to $14$ on the $\text{pH}$ scale. The basicity increases from $0$ to $14$ on the $\text{pH}$ scale. The $\text{pH}$ range for acid is from $0$ to $6$. The $\text{pH}$ range for base is from $8$ to $14$. $\text{pH}=\text{7}$ is said to be as neutral. The $\text{pH}$ range for the different type of acid and base is shown below.

Strongly acidic	$\text{pH}<4$
Weakly acidic	$4\le \text{pH}<\text{6}$
Neutral	$6\le \text{pH}<\text{8}$
Weakly basic	$8\le \text{pH}<\text{10}$
Strongly basic	$10\le \text{pH}$

The $\text{pH}$ of the solution is given as $\text{7}$.

Therefore, the given solution is neutral.

Conclusion

The nature of the given solution is neutral.

Interpretation Introduction

(b)

Interpretation:

The solution with $\text{pH = 9}$ is to be classified as strongly acidic, weakly acidic, strongly basic, weakly basic, neutral, or close to neutral.

Concept introduction:

The $\text{pH}$ scale tells about the strength of an acid and a base. It measures the concentration of the hydrogen ions. There is an inverse relationship between the $\text{pH}$ value and the concentration of the hydrogen ion. Higher the concentration of hydrogen ions, lesser the value of $\text{pH}$. There is an inverse relationship between the $\text{pOH}$ value and the concentration of the hydroxide ion. Higher the concentration of hydroxide ions, lesser the value of $\text{pOH}$.

Answer to Problem 43E

The nature of the given solution is weakly basic.

Explanation of Solution

The $\text{pH}$ scale tells about the strength of an acid and a base. The $\text{pH}$ range on $\text{pH}$ scale is from $0$ to $14$. The acidity decreases from $0$ to $14$ on the $\text{pH}$ scale. The basicity increases from $0$ to $14$ on the $\text{pH}$ scale. The $\text{pH}$ range for acid is from $0$ to $6$. The $\text{pH}$ range for base is from $8$ to $14$. $\text{pH}=\text{7}$ is said to be as neutral. The $\text{pH}$ range for the different type of acid and base is shown below.

Strongly acidic	$\text{pH}<4$
Weakly acidic	$4\le \text{pH}<\text{6}$
Neutral	$6\le \text{pH}<\text{8}$
Weakly basic	$8\le \text{pH}<\text{10}$
Strongly basic	$10\le \text{pH}$

$\text{pH}$ of the solution is $\text{9}$. A basic solution has $\text{pH}$ greater than $\text{7}$.

Therefore, the given solution is weakly basic in nature.

Conclusion

The nature of the given solution is weakly basic.

Interpretation Introduction

(c)

Interpretation:

The solution with $\text{pOH = 3}$ is to be classified as strongly acidic, weakly acidic, strongly basic, weakly basic, neutral, or close to neutral.

Concept introduction:

The $\text{pH}$ scale tells about the strength of an acid and a base. It measures the concentration of the hydrogen ions. There is an inverse relationship between the $\text{pH}$ value and the concentration of the hydrogen ion. Higher the concentration of hydrogen ions, lesser the value of $\text{pH}$. There is an inverse relationship between the $\text{pOH}$ value and the concentration of the hydroxide ion. Higher the concentration of hydroxide ions, lesser the value of $\text{pOH}$.

Answer to Problem 43E

The nature of the given solution is strongly basic in nature.

Explanation of Solution

The value of $\text{pOH}$ for the given solution is $\text{3}$.

The formula to calculate $\text{pH}$ is shown below.

$\text{pH + pOH = 14}$

Rearrange the above equation.

$\text{pH}=\text{14}-\text{pOH}$

Substitute the value of $\text{pOH}$ in the above equation.

$\begin{array}{rll}\text{pH}& =& 14-\text{pOH}\\ & =& 14-3\\ & =& 11\end{array}$

The $\text{pH}$ scale tells about the strength of an acid and a base. The $\text{pH}$ range on $\text{pH}$ scale is from $0$ to $14$. The acidity decreases from $0$ to $14$ on the $\text{pH}$ scale. The basicity increases from $0$ to $14$ on the $\text{pH}$ scale. The $\text{pH}$ range for acid is from $0$ to $6$. The $\text{pH}$ range for base is from $8$ to $14$. $\text{pH}=\text{7}$ is said to be as neutral. The $\text{pH}$ range for the different type of acid and base is shown below.

Strongly acidic	$\text{pH}<4$
Weakly acidic	$4\le \text{pH}<\text{6}$
Neutral	$6\le \text{pH}<\text{8}$
Weakly basic	$8\le \text{pH}<\text{10}$
Strongly basic	$10\le \text{pH}$

Therefore, $\text{pH}$ of solution is $11$ which is greater than $\text{7}$.

Hence, the solution is strongly basic in nature.

Conclusion

The solution is strongly basic in nature.