Chapter 13, Problem 143QP

(a)

Interpretation Introduction

Interpretation:

The given statement ‘ ${\text{CH}}_3{\text{CO}}_2\text{H}$ is the strongest acid and $\text{HF}$ is the most concentrated of the given acids’ is correct or not.

Explanation of Solution

The given acids are $\text{0}{\text{.5 M CH}}_3{\text{CO}}_2\text{H}$ and $\text{0}\text{.10 M HF}$ and their $K_{\text{a}}$ values are $1.8\times {10}^{-5}$ and $6.3\times {10}^{-4}$ , respectively.

$K_{\text{a}}$ is defined as the equilibrium constant, when an acid ionizes in water. $K_{\text{a}}$ is called acid ionization constant or acid dissociation constant. With the help of $K_{\text{a}}$ values, the strength of an acid can be determined. More the value of $K_{\text{a}}$ , stronger the acid.

${\text{CH}}_3{\text{CO}}_2\text{H}$ is not the strongest acid as its $K_{\text{a}}$ value is less than that of $\text{HF}$ . The $\text{HF}$ solution is not the most concentrated as its concentration is less than that of the ${\text{CH}}_3{\text{CO}}_2\text{H}$ solution.

Thus, the given statement is an incorrect statement.

(b)

Interpretation Introduction

Interpretation:

The given statement ‘ ${\text{CH}}_3{\text{CO}}_2\text{H}$ is the strongest acid and $\text{HF}$ is the most concentrated of the given acids’ is correct or not.

Explanation of Solution

The given acids are $\text{0}{\text{.5 M CH}}_3{\text{CO}}_2\text{H}$ and $\text{0}\text{.20 M HOCl}$ and their $K_{\text{a}}$ values are $1.8\times {10}^{-5}$ and $4.0\times {10}^{-8}$ , respectively.

${\text{CH}}_3{\text{CO}}_2\text{H}$ is not the strongest acid as its $K_{\text{a}}$ value is less than that of $\text{HOCl}$ . The $\text{HOCl}$ solution is not the most concentrated as its concentration is less than that of the ${\text{CH}}_3{\text{CO}}_2\text{H}$ solution.

Thus, the given statement is an incorrect statement.

(c)

Interpretation Introduction

Interpretation:

The given statement ‘ $\text{HOCl}$ is the strongest acid and the most concentrated is ${\text{CH}}_3{\text{CO}}_2\text{H}$ of the given acids’ is correct or not.

Explanation of Solution

The given acids are $\text{0}\text{.20 M HOCl}$ and $\text{0}{\text{.5 M CH}}_3{\text{CO}}_2\text{H}$ and their $K_{\text{a}}$ values are $4.0\times {10}^{-8}$ and $1.8\times {10}^{-5}$ , respectively.

$\text{HOCl}$ is not the strongest acid as its $K_{\text{a}}$ value is less than that of ${\text{CH}}_3{\text{CO}}_2\text{H}$ . The ${\text{CH}}_3{\text{CO}}_2\text{H}$ solution is the most concentrated as its concentrated is the maximum of the given acids.

Thus, the given statement is an incorrect statement.

(d)

Interpretation Introduction

Interpretation:

The statement ‘ $\text{HF}$ is the strongest acid and the most concentrated acid of the given acids’ is correct or not.

Explanation of Solution

The given acid is $\text{0}\text{.10 M HF}$ which has $K_{\text{a}}$ value of $6.3\times {10}^{-4}$ .

$\text{HF}$ is the strongest acid as its $K_{\text{a}}$ value is more than that of ${\text{CH}}_3{\text{CO}}_2\text{H}$ and $\text{HOCl}$ . The $\text{HF}$ solution is not the most concentrated as its concentration is less than that of the ${\text{CH}}_3{\text{CO}}_2\text{H}$ solution.

Thus, the given statement is an incorrect statement.

(e)

Interpretation Introduction

Interpretation:

The statement ‘ $\text{HF}$ is the sstrongest acid and the most concentrated acid is ${\text{CH}}_3{\text{CO}}_2\text{H}$ ’ is correct or not.

Explanation of Solution

The given acids are $\text{0}{\text{.5 M CH}}_3{\text{CO}}_2\text{H}$ and $\text{0}\text{.10 M HF}$ and their $K_{\text{a}}$ values are $1.8\times {10}^{-5}$ and $6.3\times {10}^{-4}$ , respectively.

$\text{HF}$ is the strongest acid as its $K_{\text{a}}$ value is more than that of ${\text{CH}}_3{\text{CO}}_2\text{H}$ and $\text{HOCl}$ . The ${\text{CH}}_3{\text{CO}}_2\text{H}$ solution is the most concentrated as its concentrated is the maximum of the given acids.

The given statement is the correct statement.