Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
| 1. | Given
the following acid dissociation constants,
Ka (HF) = 7.2 ´
10-4
Ka (NH4+) = 5.6 ´
10-10
determine the
equilibrium constant for the reaction below at 25 °C.
HF(aq) + NH3(aq) f NH4+(aq) +
F-(aq)
a. | 7.8 ´ 10-7 | b. | 4.0 ´
10-13 | c. | 1.3 ´ 10-8 | d. | 1.3 ´
106 | e. | 2.5 ´ 1012 | | |
|
|
| 2. | Assuming equal initial concentrations of the given species, which of the following is
the strongest acid in an aqueous solution? a. | formic acid, Ka = 1.8 ´
10-4 | b. | hydrogen phosphate ion, Ka = 3.6 ´
10-13 | c. | nitrous acid, Ka = 4.5 ´
10-4 | d. | hydrogen sulfite ion, Ka = 6.2 ´
10-8 | e. | benzoic acid, Ka = 6.3 ´
10-5 | | |
|
|
| 3. | Which
of the following chemical equations corresponds to the acid ionization constant,
Ka, for formic acid (HCO2H)? a. | HCO2-(aq) + H3O+(aq) f
HCO2H (aq) + H2O(l) | b. | HCO2-(aq) + H2O(l) f
HCO2H(aq) + OH-(aq) | c. | HCO2H(aq) + OH-(aq) f
HCO2-(aq) + H2O(l) | d. | HCO2H(aq) + H2O(l) f
HCO2-(aq) + H3O+(aq) | e. | HCO2H(aq) + H3O+(aq) f
HCO2H2+(aq) + H2O(l) | | |
|
|
| 4. | What
is the OH- concentration of an aqueous solution with a pH of 11.45? (Kw
= 1.0 ´
10-14) a. | 2.8 ´ 10-3
M | b. | 1.1 ´ 10-5
M | c. | 7.8 ´ 10-2
M | d. | 9.4 ´
10-10 M | e. | 3.5 ´ 10-12 M | | |
|
|
| 5. | Which
of the following chemical equations corresponds to Ka3 for phosphoric
acid? a. | H3PO4(aq) + H2O(l) f
H2PO4-(aq) +
H3O+(aq) | b. | PO43-(aq) + H2O(l) f
HPO42-(aq) + OH-(aq) | c. | HPO42-(aq) + H2O(l) f
PO43-(aq) + H3O+(aq) | d. | H2PO4-(aq) + H2O(l) f
HPO42-(aq) + H3O+(aq) | e. | H3PO4(aq) + 3 H2O(l) f
PO43-(aq) + 3 H3O+(aq) | | |
|
|
| 6. | All
of the following species can behave as Lewis acids EXCEPT ____. a. | CO2 | b. | F- | c. | Al(OH)3 | d. | SO3 | e. | Al3+ | | |
|
|
| 7. | The
conjugate acid of HSO4- is ____. a. | OH- | b. | H3O+ | c. | H2SO4 | d. | H2O | e. | SO42- | | |
|
|
| 8. | Which
of the following molecules or ions is the strongest acid? a. | CH3CO2H | b. | CBrH2CO2H | c. | CH3CO2- | d. | CBr3CO2H | e. | CBr2HCO2H | | |
|
|
| 9. | The
conjugate base of OH- is ____. a. | H2O | b. | H3O+ | c. | O2- | d. | H- | e. | OH- | | |
|
|
| 10. | Acids
that ionize extensively in solution are referred to as a. | Arrhenius
acids. | b. | Brønsted-Lowry acids. | c. | dissociators. | d. | strong acids. | e. | weak
electrolytes. | | |
|
|
| 11. | Which
of the following molecules or ions is amphiprotic in water? a. | HCO3- | b. | CH3CO2H | c. | HF | d. | NH4+ | e. | CN- | | |
|
|
| 12. | What
is the H3O+ concentration of an aqueous solution with a pH of
12.17? a. | 1.9 ´ 10-9
M | b. | 1.5 ´ 10-2
M | c. | 5.2 ´ 10-6
M | d. | 6.8 ´
10-13 M | e. | 1.1 M | | |
|
|
| 13. | According to the Brønsted-Lowry definition, an acid a. | is a proton
donor. | b. | is a proton acceptor. | c. | increases the
OH- concentration in an aqueous solution. | d. | increases the
H3O+ concentration in an aqueous solution. | e. | is an electron
pair-acceptor. | | |
|
|
| 14. | Which
salt forms a 0.10 M aqueous solution with the highest pH? a. | Ca(ClO4)2 | b. | NaNO3 | c. | FeCl3 | d. | NaF | e. | NH4Cl | | |
|
|
| 15. | Boric
acid has a pKa value of 9.14. What is the value of Kb for sodium
benzoate? a. | 1.4 ´
10-5 | b. | 7.2 ´ 10-10 | c. | -4.86 | d. | 4.86 | e. | 1.1 ´10-4 | | |
|
|
| 16. | According to the Brønsted-Lowry definition, a base a. | increases the
OH- concentration in an aqueous solution. | b. | is an
electron-pair donor. | c. | is a proton donor. | d. | is a proton
acceptor. | e. | increases the H3O+ concentration in an
aqueous solution. | | |
|
|
| 17. | What
is the pH of 0.015 M aqueous benzoic acid? (Ka of
C5H6CO2H = 6.3 ´ 10-5) a. | 3.03 | b. | 1.82 | c. | 6.02 | d. | 12.18 | e. | 4.20 | | |
|
|
| 18. | What
is the pH of the solution which results from mixing 25 mL of 0.30 M HF(aq) and 25 mL of 0.30 M
NaOH(aq) at 25 °C? (Ka of HF = 7.2 ´
10-4) a. | 12.02 | b. | 8.16 | c. | 5.84 | d. | 10.86 | e. | 8.31 | | |
|
|
| 19. | Which
salt forms a 0.10 M aqueous solution with the lowest pH? a. | NaCl | b. | NaF | c. | MgCO3 | d. | NH4Cl | e. | K3PO4 | | |
|
|
| 20. | The
pH of aqueous 0.30 M hypochlorous acid, HClO, is 3.99. What is the pKa of this
acid? a. | 12.80 | b. | 6.54 | c. | 10.01 | d. | 7.46 | e. | 13.30 | | |
|
|
| 21. | All
of the following compounds are acids containing chlorine. Which compound is the weakest
acid? a. | HCl | b. | HClO4 | c. | HClO2 | d. | HClO | e. | HClO3 | | |
|
|
| 22. | What
is the H3O+ concentration in 0.45 M HCN(aq)? (Ka of HCN = 4.0
´
10-10) a. | 0.45
M | b. | 4.0 ´
10-10 M | c. | 1.8 ´ 10-10 M | d. | 2.0 ´ 10-5
M | e. | 1.3 ´ 10-5
M | | |
|
|
| 23. | At 25
°C, what is the
H3O+ concentration in 0.044 M NaOH(aq)? (Kw = 1.0
´
10-14) a. | 1.36
M | b. | 2.3 ´
10-13 M | c. | 12.6 M | d. | 4.4 ´ 10-7
M | e. | 4.4 ´
10-16 M | | |
|
|
| 24. | Of
the following list of molecules and ions, which can behave as Lewis bases: BH3,
NH3, Cl-, Al3+? a. | Cl- and Al3+ | b. | NH3
and Cl- | c. | Cl- and BH3 | d. | BH3
only | e. | Al3+
and NH3 | | |
|
|
| 25. | Molecules or ions that can alternately behave as either a Brønsted-Lowry acid or
base are called a. | weak
electrolytes. | b. | polyprotic acids or bases. | c. | conjugate acids
or bases. | d. | hydronium ions. | e. | amphiprotic. | | |
|
|
| 26. | Which
of the following is never a Brønsted-Lowry acid in an aqueous solution? a. | hydrogen
chloride, HCl(g) | b. | hydrogen fluoride, HF(g) | c. | dihydrogen
sulfide, H2S(g) | d. | ammonium chloride,
NH4Cl(s) | e. | magnesium oxide, MgO(s) | | |
|
|
| 27. | What
is the pH of 2.1 ´ 10-5 M NaOH(aq) at 25 °C?
(Kw = 1.0 ´ 10-14) a. | 10.77 | b. | 4.68 | c. | -4.68 | d. | 9.32 | e. | 3.23 | | |
|
|
| 28. | A
solution is prepared by diluting 0.16 mol HNO3 with water to a volume of 1.5 L. What is
the pH of this solution? a. | -0.80 | b. | 2.24 | c. | 1.83 | d. | 0.97 | e. | 0.80 | | |
|
|
| 29. | If
you mix equal molar quantities of HF (Ka = 7.2 ´
10-4) and KCN (Kb = 2.5 ´ 10-5), the resulting solution will
be a. | neutral because
the weak acid neutralizes the weak base. | b. | basic because Kb of F- is less
than Kb of CN-. | c. | basic because
Ka of HF is greater than Kb of
CN-. | d. | basic because Ka of HF is greater than
Ka of HCN. | e. | acidic because Ka of HF is greater than
Kb of CN-. | | |
|
|
| 30. | In
the following reaction
HCO3-(aq) + H2O(l) f
CO32-(aq) + H3O+(aq)
a. | HCO3- is an acid and CO32- is its
conjugate base. | b. | H3O+ is an acid and
CO32- is its conjugate base. | c. | H3O+ is an acid and HCO3- is its conjugate
base. | d. | HCO3- is an acid and H2O is
its conjugate base. | e. | H2O is an acid and CO32- is
its conjugate base. | | |
|
|
| 31. | Which
of the following chemical equations corresponds to the base ionization constant,
Kb, for nitrite ion (NO2-)? a. | NO2-(aq) + OH-(aq) f
HNO32-(aq) | b. | NO2-(aq) + H2O(l) f
HNO2(aq) + OH-(aq) | c. | HNO2(aq) + OH-(aq) f
NO2-(aq) + H2O(l) | d. | HNO2(aq) + H2O(l) f
NO2-(aq) + H3O+(aq) | e. | NO2-(aq) + H3O+(aq) f
HNO2(aq) + H2O(l) | | |
|
|
| 32. | At 15
°C, the water
ionization constant, Kw, is 4.5 ´ 10-15. What is the H3O+
concentration in neutral water at this temperature? a. | 4.5 ´
10-15 M | b. | 2.2 M | c. | 6.7 ´ 10-8
M | d. | 2.0 ´
10-29 M | e. | 1.5 ´ 10-7 M | | |
|
|
| 33. | What
is the conjugate base of [Cr(H2O)6]3+(aq)? a. | [Cr(H2O)5H3O]4+ | b. | [Cr(H2O)5]3+ | c. | [Cr(H2O)5OH]2+ | d. | H3O+ | e. | [Cr(H2O)6]2+ | | |
|
|
| 34. | What
is the pH of 0.80 M Na3PO4(aq) at 25 °C? (Ka1 = 7.5 ´
10-3, Ka2 = 6.2 ´ 10-8, and Ka3 = 3.6 ´
10-13) a. | 7.73 | b. | 8.01 | c. | 13.13 | d. | 6.27 | e. | 0.87 | | |
|
|
| 35. | Which
salt produces a pH-neutral aqueous solution at 25 °C? a. | KF | b. | NH4Cl | c. | KBr | d. | FeCl3 | e. | NaNO2 | | |
|
|
| 36. | Assuming equal initial concentrations of the given species, which of the following
weak acids has the strongest conjugate base in an aqueous solution? a. | nitrous acid,
Ka = 4.5 ´ 10-4 | b. | hydrogen sulfite
ion, Ka = 6.2 ´ 10-8 | c. | formic acid,
Ka = 1.8 ´ 10-4 | d. | phosphoric acid,
Ka = 7.5 ´ 10-3 | e. | acetic acid,
Ka = 1.8 ´ 10-5 | | |
|