A simplified model of oceanic buffering involves two coupled equilibria derived from…
CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
A simplified model of oceanic buffering involves two coupled equilibria derived from dissolved carbon dioxide. These equilibria are shown below.
Equilibrium 1: CO2(aq)+H2O(l)⇌H+(aq)+HCO3−(aq)
Equilibrium 2: HCO3−(aq)⇌H+(aq)+CO32−(aq)
Answer the following questions about this system.
(a) For Equilibrium 1, list the conjugate acid–base pair and designate which member acts as the acid and which as the base in the forward reaction.
(b) Repeat part (a) for Equilibrium 2.
(c) Ocean water can absorb excess atmospheric CO2. Using the conjugate pairs you identified, explain—without performing numerical calculations—how an increase in dissolved CO2 can ultimately decrease the concentration of CO32−.
(d) Discuss how the coupled set of conjugate pairs enables seawater to resist large swings in pH when either an acid or a base is introduced.