Chapter 20, Problem 99A

(a)

Interpretation Introduction

Interpretation: The conjugate acid-base pair in the reaction, $N{H}_4{}^{+}\left(aq\right)+H_{2}O+\left(l\right)\to N{H}_3+H_3{O}^{+}\left(aq\right)$ .

Concept Introduction: According to Bronsted Lowry's concept an acid is a species that donates a proton while a base is a species that accepts a proton. The compound formed when a bronsted base accepts proton is conjugate acid. And the compound formed when a Bronsted acid accepts a proton is a conjugate base.

Answer to Problem 99A

The conjugate acid of $H_{2}O$ is $H_3{O}^{+}$ . And the conjugate base of $N{H}_4{}^{+}$ is $N{H}_3$ .

Explanation of Solution

In the reaction, $N{H}_4{}^{+}\left(aq\right)+H_{2}O+\left(l\right)\to N{H}_3+H_3{O}^{+}\left(aq\right)$ .

The proton, $H^{+}$ is accepted by $H_{2}O$ so it is the base. And, the corresponding conjugate acid is $H_3{O}^{+}$ .

The proton $H^{+}$ is donated by $N{H}_4{}^{+}$ so it is the acid. And the corresponding conjugate base is $N{H}_3$ .

(b)

Interpretation Introduction

Interpretation: The conjugate acid-base pair in the reaction, $H_{2}S{O}_3\left(aq\right)+N{H}_2{}^{-}\left(aq\right)\to HS{O}_3{}^{-}\left(aq\right)+N{H}_3\left(aq\right)$ .

Concept Introduction: According to Bronsted Lowry's concept an acid is a species that donates a proton while a base is a species that accepts a proton. The compound formed when a bronsted base accepts proton is conjugate acid. And the compound formed when a Bronsted acid accepts a proton is a conjugate base.

Answer to Problem 99A

The conjugate acid of $N{H}_2{}^{-}$ is $N{H}_3$ . And the conjugate base of $HS{O}_3$ is $HS{O}_3{}^{-}$ .

Explanation of Solution

In the reaction, $H_{2}S{O}_3\left(aq\right)+N{H}_2{}^{-}\left(aq\right)\to HS{O}_3{}^{-}\left(aq\right)+N{H}_3\left(aq\right)$

The proton is accepted by $N{H}_2{}^{-}$ and so it is the base. The corresponding conjugate acid is $N{H}_3$ . While the proton is donated by $HS{O}_3$ and the corresponding conjugate base is $HS{O}_3{}^{-}$ .

(c)

Interpretation Introduction

Interpretation: The conjugate acid-base pair in the reaction, $HN{O}_3\left(aq\right)+I^{-}\left(aq\right)\to N{O}_3{}^{-}\left(aq\right)+HI\left(aq\right)$ .

Concept Introduction: According to Bronsted Lowry's concept an acid is a species that donates a proton while a base is a species that accepts a proton. The compound formed when a bronsted base accepts proton is conjugate acid. And the compound formed when a Bronsted acid accepts a proton is a conjugate base.

Answer to Problem 99A

The conjugate acid of $I^{-}$ is $HI$ . And the conjugate base of $HN{O}_3$ is $N{O}_3{}^{-}$ .

Explanation of Solution

In the reaction, $HN{O}_3\left(aq\right)+I^{-}\left(aq\right)\to N{O}_3{}^{-}\left(aq\right)+HI\left(aq\right)$

The proton is donated by $HN{O}_3$ and so it is the acid. And the corresponding conjugate base is $N{O}_3{}^{-}$ . The proton is accepted by $I^{-}$ and so it is the base. The corresponding conjugate acid is HI.