AP Chem Acids and Bases
The net ionic equation for the reaction between silver carbonate and hydrochloric acid is... A: Ag₂CO₃(s)+2H⁺+2Cl⁻→2AgCl(s)+H₂O+CO₂(g) B: 2Ag⁺+CO₃²⁻+2H⁺+2Cl⁻→2AgCl(s)+H₂O+CO₂(g) C: CO₃²⁻+2H⁺→H₂O+CO₂(g) D: Ag⁺+Cl⁻→AgCl(s) E: Ag₂CO₃(s)+2H⁺→2Ag⁺+H₂CO₃
A: Ag₂CO₃(s)+2H⁺+2Cl⁻→2AgCl(s)+H₂O+CO₂(g)
HC₂H₃O₂(aq)+CN⁻(aq)→HCN(aq)+C₂H₃O₂⁻(aq) The reaction represented above has an equilibrium constant equal to 3.7x10⁴. Which of the following can be concluded from this information? A: CN⁻(aq) is a stronger base than C₂H₃O₂⁻(aq) B: HCN(aq) is a stronger acid than HC₂H₃O₂(aq) C: the conjugate base of CN⁻(aq) is C₂H₃O₂⁻(aq) D: the equilibrium constant will increase with an increase in temperature E: the pH of a solution containing equimolar amounts of CN⁻(aq) and HC₂H₃O₂(aq) is 7.0
A: CN⁻(aq) is a stronger base than C₂H₃O₂⁻(aq)
The equilibrium constant for the reaction represented by the equation below is greater than 1.0. Which of the following gives the correct relative strengths of the acids and bases in the reaction? H₂PO₄⁻+HBO₃²⁻→HPO₄²⁻+H₂BO³⁻ Acids Bases A: H₂PO₄⁻>H₂BO₃⁻and HBO₃²⁻>HPO₄²⁻ B: H₂BO₃⁻>H₂PO₄⁻and HBO₃²⁻>HPO₄²⁻ C: H₂PO₄⁻>H₂BO₃⁻and HPO₄²⁻>HBO₃²⁻ D: H₂BO₃⁻>H₂PO₄⁻and HPO₄²⁻>HBO₃²⁻ E: H₂PO₄⁻=H₂BO₃⁻and HPO₄²⁻=HBO₃²⁻
A: H₂PO₄⁻>H₂BO₃⁻and HBO₃²⁻>HPO₄²⁻
To determine the molar mass of a solid monoprotic acid, a student titrated a weighed sample of the acid with standardized aqueous NaOH. Which of the following could explain why the student obtained a molar mass that was too large? I. Failure to rinse all acid from the weighing paper into the titration vessel II. Addition of more water than was needed to dissolve the acid III. Addition of some base beyond the equivalence point A: I only B: III only C: I and II only D: II and III only E: I, II, and III
A: I only
A buffer at a pH>8. A: NH₃ and NH₄Cl B: H₃PO₄ and NaH₂PO₄ C: HCl and NaCl D: NaOH and NH₃ E: NH₃ and HC₂H₃O₂ (acetic acid)
A: NH₃ and NH₄Cl
What part of the curve corresponds to the optimum buffer action for the acetic acid/acetate pair? A: Point V B: Point X C: Point Z D: Along all of section WY E: Along all of section YZ
A: Point V
A solution prepared to be initially 1 M in NaCl and 1 M in HCl. A: a solution with a pH less than 7 that is not a buffer solution B: a buffer solution with a pH between 4 and 7 C: a buffer solution with a pH between 7 and 10 D: a solution with a pH greater than 7 that is not a buffer solution D: a solution with a pH of 7
A: a solution with a pH less than 7 that is not a buffer solution
A solution of calcium hypochlorite, a common additive to swimming-pool water, is... A: basic because of the hydrolysis of the OCl⁻ ion B: basic because Ca(OH)₂ is a weak and insoluble base C: neutral if the concentration is kept below 0.1 molar D: acidic because of the hydrolysis of the Ca²⁺ ions E: acidic because the acid HOCl is formed
A: basic because of the hydrolysis of the OCl⁻ ion
Commercial vinegar was titrated with NaOH solution to determine the content of acetic acid, HC₂H₃O₂. For 20.0 milliliters of the vinegar, 32.0 milliliters of 0.500-molar NaOH solution was required. What was the concentration of acetic acid in the vinegar if no other acid was present? A: 1.60M B: 0.800M C: 0.640M D: 0.600M E: 0.400M
B: 0.800M
Equal volumes of 0.10-molar H₃PO₄ and 0.20-molar KOH are mixed. After equilibrium is established, the type of ion a solution in largest concentration, other than the K⁺ ion, is... A: H₂PO₄⁻ B: HPO₄⁻ C: PO₄³⁻ D: OH⁻ E: H₃O⁺
B: HPO₄⁻
Which, if any, of the following species is in the greatest concentration in 0.100-molar solution of H₂SO₄ in water? A: H₂SO₄ molecules B: H₃O⁺ ions C: HSO₄⁻ ions D: SO₄²⁻ ions E: all species are in equilibrium and therefore have the same concentrations
B: H₃O⁺ ions
A buffer at a pH<6. A: NH₃ and NH₄Cl B: H₃PO₄ and NaH₂PO₄ C: HCl and NaCl D: NaOH and NH₃ E: NH₃ and HC₂H₃O₂ (acetic acid)
B: H₃PO₄ and NaH₂PO
Mixtures that would be considered buffers include which of the following? I. 0.10 M HCl + 0.10 M NaCl II. 0.10 M HF + 0.10 M NaF III. 0.10 M HBr + 0.10 M NaBr A: I only B: II only C: III only D: I and II E: II and III
B: II only
Which of the following is the correct equilibrium expression for the hydrolysis of CO₃²⁻? A: K=[HCO₃⁻] / ([CO₃²⁻][H₃O⁺]) B: K=([HCO₃⁻][OH⁻]) / [CO₃²⁻] C: K=([CO₃²⁻ ][OH⁻]) / [HCO₃⁻] D: K=[CO₃²⁻] / ([CO₂][OH⁻]²) E: K=([CO₃²⁻][H₃O⁺]) / [HCO₃⁻]
B: K=([HCO₃⁻][OH⁻]) / [CO₃²⁻]
A pure white crystalline solid dissolves in water to yield a basic solution that liberates a gas when excess acid is added to it. On the basis of this information, the solid could be... A: KNO₃ B: K₂CO₃ C: KOH D: KHSO₄ E: KCl
B: K₂CO₃
A 1-molar solution of which of the following salts has the highest pH? A: NaNO₃ B: Na₂CO₃ C: NH₄Cl D: NaHSO₄ E: Na₂SO₄
B: Na₂CO₃
A solution prepared to be initially 0.5 M in CH₃COOH and 1 M in CH₃COONa. A: a solution with a pH less than 7 that is not a buffer solution B: a buffer solution with a pH between 4 and 7 C: a buffer solution with a pH between 7 and 10 D: a solution with a pH greater than 7 that is not a buffer solution D: a solution with a pH of 7
B: a buffer solution with a pH between 4 and 7
When dilute nitric acid was added to a solution of one of the following chemicals, a gas was evolved. This gas turned a drop of limewater, Ca(OH)2, cloudy, due to the formation of a white precipitate. The chemical was... A: household ammonia, NH₃ B: baking soda, NaHCO₃ C: table salt, NaCl D: epsom salts, MgSO₄x7H₂O E: bleach, 5% NaOCl
B: baking soda, NaHCO₃
When phenolphthalein is used as the indicator in a titration of an HCl solution with a solution of NaOH, the indicator undergoes a color change from clear to red at the end point of the titration. This color change occurs abruptly because... A: phenolphthalein is a very strong acid that is capable of rapid dissociation B: the solution being titrated undergoes a large pH change near the end point of the titration C: phenolphthalein undergoes an irreversible reaction in basic solution D: OH⁻ acts as a catalyst for the decomposition of phenolphthalein E: phenolphthalein is involved in the rate-determining step of the reaction between H₃O⁺ and OH⁻
B: the solution being titrated undergoes a large pH change near the end point of the titration
At 25°C, aqueous solutions with a pH of 8 have a hydroxide ion concentration, [OH⁻], of... A: 1 × 10⁻¹⁴ M B: 1 × 10⁻⁸ M C: 1 × 10⁻⁶ M D: 1M E: 8M
C: 1 × 10⁻⁶ M
H₂C₂O₄+2H₂O→2H₃O⁺+C₂O₄²⁻ Oxalic acid, H₂C₂O₄, is a diprotic acid with K1=5 x 10⁻₂ and K2=5 x 10⁻⁵. Which of the following is equal to the equilibrium constant for the reaction represented above? A: 5 x 10⁻² B: 5 x 10⁻⁵ C: 2.5 x 10⁻⁶ D: 5 x 10⁻⁷ E: 2.5 x 10⁻⁸
C: 2.5 x 10⁻⁶
What volume of 0.150-molar HCl is required to neutralize 25.0 milliliters of 0.120-molar Ba(OH)₂? A: 20.0 mL B: 30.0 mL C: 40.0 mL D: 60.0 mL E: 80.0 mL
C: 40.0 mL
A 0.20-molar solution of a weak monoprotic acid, HA, has a pH of 3.00. The ionization constant of this acid is... A: 5.0 x 10⁻⁷ B: 2.0 x 10⁻⁷ C: 5.0 x 10⁻⁶ D: 5.0 x 10⁻³ E: 2.0 x 10⁻³
C: 5.0 x 10⁻⁶
How can 100. mL of sodium hydroxide solution with a pH of 13.00 be converted to a sodium hydroxide solution with a pH of 12.00? A: By diluting the solution with distilled water to a total volume of 108 mL B: By diluting the solution with distilled water to a total volume of 200 mL C: By diluting the solution with distilled water to a total volume of 1.00 L D: By adding 100. mL of 0.10 M HCl E: By adding 100. mL of 0.10 M NaOH
C: By diluting the solution with distilled water to a total volume of 1.00 L
The solution with the lowest pH. A: NH₃ and NH₄Cl B: H₃PO₄ and NaH₂PO₄ C: HCl and NaCl D: NaOH and NH₃ E: NH₃ and HC₂H₃O₂ (acetic acid)
C: HCl and NaCl
Correct procedures for a titration include which of the following? I. Draining a pipet by touching the tip to the side of the container used for the titration II. Rinsing the buret with distilled water just before filling it with the liquid to be titrated III. Swirling the solution frequently during the titration A: I only B: II only C: I and III only D: II and III only E: I, II, and III
C: I and III only
Each of the following can act as both a Brönsted acid and a Brönsted base EXCEPT... A: HCO₃⁻ B: H₂PO₄⁻ C: NH₄⁺ D: H₂O E: HS⁻
C: NH₄⁺
A molecule or an ion is classified as a Lewis acid if it... A: accepts a proton from water B: accepts a pair of electrons to form a bond C: donates a pair of electrons to form a bond D: donates a proton to water E: has resonance Lewis electron-dot structures
C: donates a pair of electrons to form a bond
2NH₃→NH₄⁺+NH₂⁻ In liquid ammonia, the reaction represented above occurs. In the reaction NH₄⁺ acts as... A: a catalyst B: both an acid and a base C: the conjugate acid of NH₃ D: the reducing agent E: the oxidizing agent
C: the conjugate acid of NH₃
In the titration of a weak acid of unknown concentration with a standard solution of a strong base, a pH meter was used to follow the progress of the titration. Which of the following is true for this experiment? A: the pH is 7 at the equivalence point B: the pH at the equivalence point depends on the indicator used C: the graph of pH versus volume of base added rises gradually at first and then much more rapidly D: the graph of pH versus volume of base added shows no sharp rise E: the [H⁺] at the equivalence point equals the ionization constant of the acid
C: the graph of pH versus volume of base added rises gradually at first and then much more rapidly
The pH of 0.1-molar ammonia is approximately... A: 1 B: 4 C: 7 D: 11 E: 14
D: 11
What is the H+(aq) concentration in 0.05M HCN(aq)? (The Ka for HCN is 5.0 x 10⁻¹⁰) A: 2.5 x 10⁻¹¹ B: 2.5 x 10⁻¹⁰ C: 5.0 x 10⁻¹⁰ D: 5.0 x 10⁻⁶ E: 5.0 x 10⁻⁴
D: 5.0 x 10⁻⁶
What is the pH of a 1.0x10⁻²-molar solution of HCN? (Ka=4.0x10⁻¹⁰) A: 10 B: between 7 and 10 C: 7 D: Between 4 and 7 E: 4
D: Between 4 and 7
The safest and most effective emergency procedure to treat an acid splash on skin is to do which of the following immediately? A: Dry the affected area with paper towels B: Sprinkle the affected area with powdered Na₂SO₄(s) C: Flush the affected area with water and then with a dilute NaOH solution D: Flush the affected area with water and then with a dilute NaHCO₃ solution E: Flush the affected area with water and then with a dilute vinegar solution
D: Flush the affected area with water and then with a dilute NaHCO₃ solution
H₃PO₄ - K=7x10⁻³ H₂PO₄⁻ - K=8x10⁻⁸ HPO₄²⁻ - K=5x10⁻¹³ On the basis of the information above, a buffer with a pH = 9 can best be made by using... A: pure NaH₂PO₄ B: H₃PO₄+H₂PO₄⁻ C: H₂PO₄⁻+PO₄³⁻ D: H₂PO₄⁻+HPO₄²⁻ E: HPO₄²⁻+PO₄³⁻
D: H₂PO₄⁻+HPO₄²⁻
All of the following species can function as Brönsted-Lowry bases in solution EXCEPT... A: H₂O B: NH₃ C: S²⁻ D: NH₄⁺ E: HCO₃⁻
D: NH₄⁺
Which of the following indicators is the best choice for this titration? A: Methyl orange B: Methyl red C: Bromthymol blue D: Phenolphthalein E: Alizarin
D: Phenolphthalein
A solution prepared to be initially 1 M in Na₂CO₃ and 1 M in CH₃COONa. A: a solution with a pH less than 7 that is not a buffer solution B: a buffer solution with a pH between 4 and 7 C: a buffer solution with a pH between 7 and 10 D: a solution with a pH greater than 7 that is not a buffer solution D: a solution with a pH of 7
D: a solution with a pH greater than 7 that is not a buffer solution
If the dissociation constant, K, for an acid HA is 8x10⁻⁴ at 25°C, what percent of the acid is dissociated in a o.50-molar solution of HA at 25°C? A: 0.08% B: 0.2% C: 1% D: 2% E: 4%
E: 4%
Which of the following ions is the strongest Lewis acid? A: Na⁺ B: Cl⁻ C: CH₃COO⁻ D: Mg²⁺ E: Al³⁺
E: Al³⁺
Ascorbic acid H₂C₆H₆O₆(s), is a diprotic acid with K1=7.9×10⁻⁵ and K2=1.6×10⁻¹². In a 0.005 M aqueous solution of ascorbic acid, which of the following species is present in the lowest concentration? A: H₂O(l) B: H₃O⁺(aq) C: H₂C₆H₆O₆(aq) D: HC₆H₆O₆⁻(aq) E: C₆H₆O₆²⁻(aq)
E: C₆H₆O₆²⁻(aq)
The net ionic equation for the reaction that occurs during the titration of nitrous acid with sodium hydroxide is... A: HNO₂+Na⁺+OH⁻→NaNO₂+H₂O B: HNO₂+NaOH→Na⁺+NO₂⁻+H₂O C: H⁺+OH⁻→H₂O D: HNO₂+H₂O→NO₂⁻+H₃O⁺ E: HNO₂+OH⁻→NO₂⁻+H₂O
E: HNO₂+OH⁻→NO₂⁻+H₂O
Which of the following reactions does NOT proceed significantly to the right in aqueous solutions? A: H₃O⁺+OH⁻→2H₂O B: HCN+OH⁻→H₂O+CN⁻ C: Cu(H₂O)₄²⁺+4NH₃→Cu(NH₃)₄²⁺+4H₂O D: H₂SO₄+H₂O→H₃O⁺+HSO₄⁻ E: H₂O+HSO₄⁻→H₂SO₄+OH⁻
E: H₂O+HSO₄⁻→H₂SO₄+OH⁻
Which of the following acids can be oxidized to form a stronger acid? A: H₃PO₄ B: HNO₃ C: H₂CO₃ D: H₃BO₃ E: H₂SO₃
E: H₂SO₃
HSO₄⁻+H₂O→H₃O⁺+SO₄²⁻ In the equilibrium represented above, the species that act as bases include which of the following? I.HSO₄⁻ II.H₂O III.SO₄²⁻ A: II only B: III only C: I and II D: I and III E: II and III
E: II and III
The most nearly neutral solution. A: NH₃ and NH₄Cl B: H₃PO₄ and NaH₂PO₄ C: HCl and NaCl D: NaOH and NH₃ E: NH₃ and HC₂H₃O₂ (acetic acid)
E: NH₃ and HC₂H₃O₂ (acetic acid)
As the number of oxygen atoms increases in any series of oxygen acids, such as HXO, HXO₂, HXO3, which of the following is generally true? A: the acid strength varies unpredictably B: the acid strength decreases only if X is a nonmetal C: the acid strength decreases only if X is a metal D: the acid strength decreases whether X is a nonmetal or a metal E: the acid strength increases
E: the acid strength increases