a. Write equilibrium expressions for the following reactions:

i. C₆H₅COOH(aq) ⇌ H⁺ (aq) + C₆H₅COO–(aq)

ii. HCO₃^–(aq) ⇌ H⁺(aq) + CO₃^2–(aq)    

iii. NH₄⁺(aq) ⇌ H⁺(aq) + NH₃(aq)

b. Look at Table 21.2. For the following acids or ions (shown in the left-hand column) work out which species in the equilibrium are Brønsted–Lowry acids and which are their conjugate bases:

i. Hydrated Fe³⁺ ion

ii. Nitric(III) (acid)

iii. Carbonic (acid)

iv. Hydrogensilicate ion.