14.1 Brønsted-Lowry Acids and Bases

Write equations that show NH₃ as both a conjugate acid and a conjugate base.

Show by suitable net ionic equations that each of the following species can act as a Brønsted-Lowry acid:

(a) $\text{H}_{3} \text{O}^{+}$

(b) HCl

(c) NH₃

(d) CH₃CO₂H

(e) $\text{NH}_{4} ^{+}$

(f) $\text{HSO}_{4} ^{−}$

Show by suitable net ionic equations that each of the following species can act as a Brønsted-Lowry base:

(a) H₂O

(b) OH⁻

(c) NH₃

(d) CN⁻

(e) S²⁻

(f) $\text{H}_{2} \text{PO}_{4} ^{−}$

What is the conjugate acid of each of the following? What is the conjugate base of each?

(a) OH⁻

(b) H₂O

(c) $\text{HCO}_{3} ^{−}$

(d) NH₃

(e) $\text{HSO}_{4} ^{−}$

(f) H₂O₂

(g) HS⁻

(h) $\text{H}_{5} \text{N}_{2} ^{+}$

Identify and label the Brønsted-Lowry acid, its conjugate base, the Brønsted-Lowry base, and its conjugate acid in each of the following equations:

(a) $\text{HNO}_{3} + \text{H}_{2} \text{O} \rightarrow \text{H}_{3} \text{O}^{+} + \text{NO}_{3} ^{−}$

(b) $\text{CN}^{−} + \text{H}_{2} \text{O} \rightarrow \text{HCN} + \text{OH}^{−}$

(c) $\text{H}_{2} \text{SO}_{4} + \text{Cl}^{−} \rightarrow \text{HCl} + \text{HSO}_{4} ^{−}$

(d) $\text{HSO}_{4} ^{−} + \text{OH}^{−} \rightarrow \text{SO}_{4} ^{\text{2}−} + \text{H}_{2} \text{O}$

(e) $\text{O}^{2−} + \text{H}_{2} \text{O} \rightarrow 2 OH^{−}$

(f) $\left[\text{Cu} \left(\text{H}_{2} \text{O}\right)_{3} \left(\text{OH}\right)\right]^{+} + \left[\text{Al} \left(\text{H}_{2} \text{O}\right)_{6}\right]^{3+} \rightarrow \left[\text{Cu} \left(\text{H}_{2} \text{O}\right)_{4}\right]^{2+} + \left[\text{Al} \left(\text{H}_{2} \text{O}\right)_{5} \left(\text{OH}\right)\right]^{2+}$

(g) $\text{H}_{2} \text{S} + \text{NH}_{2} ^{−} \rightarrow \text{HS}^{−} + \text{NH}_{3}$

What are amphiprotic species? Illustrate with suitable equations.

State which of the following species are amphiprotic and write chemical equations illustrating the amphiprotic character of these species.

(a) $\text{NH}_{3}$

(b) $\text{HPO}_{4} ^{\text{2}−}$

(c) Br⁻

(d) $\text{NH}_{4} ^{+}$

(e) $\text{AsO}_{4} ^{\text{3}−}$