According to the Brønsted-Lowry theory, which of the following acts as an amphiprotic species?
Anonymous Quiz
5%
CO₃²⁻
39%
HCO₃⁻
34%
NH₄⁺
21%
H₃O⁺
❤4👍1
1 In the reaction BF₃ + NH₃---> F₃B-NH₃, which statement correctly describes the behavior of the reactants based on the Lewis concept?
Anonymous Quiz
28%
BF₃ acts as a Lewis acid because it accepts a proton.
13%
NH₃ acts as a Lewis base because it donates a proton.
42%
BF₃ acts as a Lewis acid because it accepts an electron pair.
17%
NH₃ acts as a Lewis acid because it donates an electron pair.
❤6
Which one of the following is a conjugate acid-base pair in the reaction:
HNO₂(aq) + H₂O(l) ⇌ NO₂⁻(aq) + H₃O⁺(aq)
HNO₂(aq) + H₂O(l) ⇌ NO₂⁻(aq) + H₃O⁺(aq)
Anonymous Quiz
11%
HNO₂ and H₂O
21%
HNO₂ and H₃O⁺
25%
H₂O and NO₂⁻
43%
HNO₂ and NO₂⁻
❤4🥰2
At a certain temperature, the ion-product constant of water (Kw) is 4.0 × 10⁻¹⁴. What is the H₃O⁺ ion concentration of pure neutral water at this temperature?
Anonymous Quiz
23%
1.0 × 10⁻⁷ M
32%
2.0 × 10⁻⁷ M
34%
4.0 × 10⁻⁷ M
11%
1.0 × 10⁻¹⁴ M
❤5👍1
What is the pH of a 0.10 M nitrous acid (HNO₂) solution if its acid dissociation constant (Ka) is 4.5 × 10⁻⁴?
Anonymous Quiz
15%
1.00
32%
2.17
18%
3.35
35%
4.50
❤4
What will happen to the pH and the percent ionization of an acetic acid (CH₃COOH) solution if a small amount of solid sodium acetate (CH₃COONa) is added?
Anonymous Quiz
50%
pH increases, percent ionization decreases.
25%
pH decreases, percent ionization increases.
11%
Both pH and percent ionization increase.
14%
Both pH and percent ionization decrease.
❤3
Which one of the following combinations of aqueous solutions can form an effective buffer mixture system?
Anonymous Quiz
20%
HCl and NaCl
25%
NH₃ and NH₄Cl
10%
NaOH and NaCl
45%
CH₃COOH and HCl
❤5👍1
A chemist prepares a buffer solution containing 0.20 M HF and 0.20 M NaF. If the Ka of HF is 6.8 × 10⁻⁴, what is the pH of this buffer system? (log(6.8 × 10⁻⁴) = −3.17)
Anonymous Quiz
0%
2.17
62%
3.17
14%
4.17
24%
7.00
❤3🤔1
Which of the following salts dissolves in water to form an alkaline (basic) solution?
Anonymous Quiz
19%
NH₄Cl
21%
KNO₃
40%
CH₃COONa
19%
NaCl
❤4
For a salt derived from a weak acid (HA) and a strong base (BOH), which expression correctly defines the hydrolysis constant (Kh)?
Anonymous Quiz
32%
Kh = Kw / Ka
23%
Kh = Kw / Kb
19%
Kh = Kw × Ka
26%
Kh = Ka / Kw
❤4
An aqueous solution of ammonium acetate (CH₃COONH₄) is found to be almost exactly neutral (pH ≈ 7). This behavior occurs because:
Anonymous Quiz
7%
Neither the cation nor the anion undergoes hydrolysis.
67%
The Ka value of CH₃COOH is approximately equal to the Kb value of NH₃.
22%
It is a salt derived from a strong acid and a strong base.
4%
Acetate ions neutralize the ammonium ions directly.
❤3🙏1
Phenolphthalein is an acid-base indicator with a pH transition range of 8.2 to 10.0. For which type of titration is it best suited?
Anonymous Quiz
22%
Strong acid titrated with a weak base.
33%
Weak acid titrated with a strong base.
33%
Weak acid titrated with a weak base.
11%
Dilute hydrochloric acid titrated with ammonia solution.
❤4
What volume of a 0.15 M Ba(OH)₂ solution is required to completely neutralize 30.0 mL of a 0.20 M HCl solution?
Anonymous Quiz
16%
10.0 mL
32%
20.0 mL
20%
30.0 mL
32%
40.0 mL
❤4
During a titration of a weak base with a strong acid, the pH at the equivalence point is:
Anonymous Quiz
7%
Exactly 7.0 due to complete neutralization.
24%
Greater than 7.0 due to the excess strong acid.
63%
Less than 7.0 due to the salt cation hydrolysis.
5%
Independent of the strength of the acid used.
❤5