Chapter 17, Problem 10E

Interpretation Introduction

(a)

Interpretation:

The conjugate base of ${\text{CH}}_{\text{3}}\text{COOH}$ is to be stated.

Concept introduction:

According to Brønsted theory of acids and bases, a substance that donates hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ to any other substance is known as an acid. On the other hand, a substance that accepts hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ is known as base. The species that remains after donating proton by a bronsted acid is known as its conjugate base.

Answer to Problem 10E

The conjugate base of acetic acid $\left({\text{CH}}_{\text{3}}\text{COOH}\right)$ is ${\text{CH}}_{\text{3}}{\text{COO}}^{-}$.

Explanation of Solution

The conjugate base of ${\text{CH}}_{\text{3}}\text{COOH}$ is formed when an ${\text{H}}^{+}$ ion is removed from it as shown below.

$\begin{array}{l}{\text{CH}}_{\text{3}}\text{COOH}\to {\text{CH}}_{\text{3}}{\text{COO}}^{-}+{\text{H}}^{+}\\ \text{Acid}\text{Conjugate}\text{base}\end{array}$

Therefore, the conjugate base of ${\text{CH}}_{\text{3}}\text{COOH}$ is ${\text{CH}}_{\text{3}}{\text{COO}}^{-}$.

Conclusion

The conjugate base of the acetic acid is ${\text{CH}}_{\text{3}}{\text{COO}}^{-}$.

Interpretation Introduction

(b)

Interpretation:

The conjugate acid of ${\text{CN}}^{-}$ is to be stated.

Concept introduction:

According to Brønsted theory of acids and bases, a substance that donates hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ to any other substance is known as an acid. On the other hand, a substance that accepts hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ is known as base. The species that remains after donating proton by a bronsted acid is known as its conjugate base.

Answer to Problem 10E

The conjugate acid of cyanide ion $\left({\text{CN}}^{-}\right)$ is $\text{HCN}$.

Explanation of Solution

The conjugate acid of ${\text{CN}}^{-}$ is formed when an ${\text{H}}^{+}$ ion is added to it as shown below.

$\begin{array}{l}{\text{CN}}^{-}+{\text{H}}^{+}\to \text{HCN}\\ \text{Base}\text{Conjugate}\text{acid}\end{array}$

Therefore, the conjugate acid of ${\text{CN}}^{-}$ is $\text{HCN}$.

Conclusion

The conjugate acid of cyanide ion is $\text{HCN}$.

Interpretation Introduction

(c)

Interpretation:

The conjugate base of ${\text{H}}_{\text{2}}\text{S}$ is to be stated.

Concept introduction:

According to Brønsted theory of acids and bases, a substance that donates hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ to any other substance is known as an acid. On the other hand, a substance that accepts hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ is known as base. The species that remains after donating proton by a bronsted acid is known as its conjugate base.

Answer to Problem 10E

The conjugate base of ${\text{H}}_{\text{2}}\text{S}$ is ${\text{HS}}^{-}$.

Explanation of Solution

The conjugate base of ${\text{H}}_{\text{2}}\text{S}$ is formed when an ${\text{H}}^{+}$ ion is removed from it as shown below.

$\begin{array}{l}{\text{H}}_{\text{2}}\text{S}\to {\text{HS}}^{-}+{\text{H}}^{+}\\ \text{Acid}\text{Conjugate}\text{base}\end{array}$

Therefore, the conjugate base of ${\text{H}}_{\text{2}}\text{S}$ is ${\text{HS}}^{-}$.

Conclusion

The conjugate base of the acid ${\text{H}}_{\text{2}}\text{S}$ is ${\text{HS}}^{-}$.

Interpretation Introduction

(d)

Interpretation:

The conjugate acid of ${\text{HCO}}_3^{-}$ is to be stated.

Concept introduction:

According to Brønsted theory of acids and bases, a substance that donates hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ to any other substance is known as an acid. On the other hand, a substance that accepts hydrogen ions $\left({\text{H}}^{\text{+}}\right)$ is known as base. The species that remains after donating proton by a bronsted acid is known as its conjugate base.

Answer to Problem 10E

The conjugate acid of ${\text{HCO}}_3^{-}$ is ${\text{H}}_2{\text{CO}}_3$.

Explanation of Solution

The conjugate acid of ${\text{HCO}}_3^{-}$ is formed when an ${\text{H}}^{+}$ ion is added to it as shown below.

$\begin{array}{l}{\text{HCO}}_3^{-}+{\text{H}}^{+}\to {\text{H}}_2{\text{CO}}_3\\ \text{Base}\text{Conjugate}\text{acid}\end{array}$

Therefore, the conjugate acid of ${\text{HCO}}_3^{-}$ is ${\text{H}}_2{\text{CO}}_3$.

Conclusion

The conjugate acid of ${\text{HCO}}_3^{-}$ is ${\text{H}}_2{\text{CO}}_3$.