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HomeReuschVirtual Textbook Practice ProblemsAcid-Base Equilibrium Relationships

Brønsted Acid-Base Equilibria

Five acid-base equilibria are shown below. In each equation the two reactants on the left side of the equilibrium are designated A & B; the two reactants on the right are designated C & D. In the first equation, the charges of ionic reactants are shown; for the other four reactions these charges are omitted. In the fifth equation, H2CO3 is reactant C and NH3 is D. NaCl is an inert product. A table of pKa values is provided at the bottom of the page.
For each equilibrium, three questions are posed:

  • Which reactants function as Brønsted acids? [Two letters (A through D) should be entered in the answer box.]
  • Which reactant is the stronger base? [One letter (A through D) should be entered in the answer box.]
  • Which side of the equilibrium is favored? [Two letters (AB or CD) should be entered in the answer box.]
Reactant A + Reactant B Reactant C + Reactant D Which act
as acids?
Which is the
stronger base?
Which side
is favored?
(CH3)3COH + Na(+) OH(–) (CH3)3CO(–) Na(+) + H2O Enter two letters
Enter one letter
Enter two letters
HF + CH3CO2Na NaF + CH3CO2H Enter two letters
Enter one letter
Enter two letters
NaSH + C6H5OH H2S + C6H5ONa Enter two letters
Enter one letter
Enter two letters
NaCN + Na2HPO4 Na3PO4 + HCN Enter two letters
Enter one letter
Enter two letters
NaHCO3 + NH4Cl H2CO3 + NH3 + NaCl Enter two letters
Enter one letter
Enter two letters


Acid HCl H3O(+) H3PO4 HF CH3CO2H H2CO3 H2S NH4(+) HCN C6H5OH H2O (CH3)3COH NH3
pKa -7 -1.7 2.2
7.2
12.3
3.2 4.7 6.4
10.3
7.0 9.2 9.3 10.0 15.7 19 34