Deck 14: Acid-Base Equilibria

Question 1

If 10 mL of a 1 M HI solution is added to 5 mL of a 1 M KOH solution, the resulting solution would be _____. Outcome # 10) DOK 2)

A) acidic
B) basic
C) neutral

Answer 1

acidic

Question 2

When titrating a weak acid with a strong base, approximately where would the pH be observed when reaching the equivalence point? Outcome # 4) DOK 2)

A) at the equivalence point, the pH is greater than 7
B) at the equivalence point, the pH is equal to 7
C) at the equivalence point, the pH is less than 7

Answer 2

at the equivalence point, the pH is greater than 7

Question 3

Which of the following is a typical type of electrode found on a pH meter? Outcome # 7) DOK 1)

A) gold electrode
B) glass electrode
C) silver electrode

Answer 3

glass electrode

Question 4

Phenolphthalein can be used as an _____ in acid-base titrations. Outcome # 4) DOK 1)

A) equivalence point
B) end-point
C) indicator

Question 5

What is the pH of a solution if 10 mL of a 1 M HCl solution is added to 10 mL of a 1 M NaOH solution? Outcome # 10) DOK 2)

A) 14
B) 7
C) 0

Question 6

When phosphoric acid is dissolved in water, what is the conjugate acid that is formed? Outcome # 3) DOK 2)

A) H₂PO₄^-
B) H₃O⁺
C) HPO₄^2-

Question 7

When red litmus paper is in contact with a base, the litmus paper will turn _____. Outcome # 4) DOK 1) Paired item 1)

A) orange
B) green
C) blue

Question 8

Which of the following is an electronic device used to measure the hydrogen ion activity in aqueous solutions? Outcome # 7) DOK 1)

A) pH meter
B) potentiometer
C) ammeter

Question 9

When titrating a weak base with a strong acid, approximately where would the pH be observed when reaching the equivalence point? Outcome # 4) DOK 2) Paired item 1)

A) at the equivalence point, the pH is greater than 7
B) at the equivalence point, the pH is equal to 7
C) at the equivalence point, the pH is less than 7

Question 10

What are the products formed at the equivalence point when titrating a strong acid with a strong base? Outcome # 4) DOK 2)

A) salt and water
B) the solution is neutral, so water only
C) no products are formed

Question 11

When blue litmus paper is in contact with an acid, the litmus paper will turn _____. Outcome # 4) DOK 1)

A) orange
B) red
C) green

Question 12

Rank the following oxoacids in order of increasing acidity: HClO₂, HClO₄, HClO, HClO₃. Outcome # 3) DOK 2)

A) HClO, HClO₂, HClO₃, HClO₄
B) HClO₄, HClO₂, HClO, HClO₃
C) HClO₄, HClO₃, HClO₂, HClO

Question 13

When titrating a strong acid with a strong base, approximately where would the pH be observed when reaching the equivalence point? Outcome # 4) DOK 2) Paired item 2)

A) at the equivalence point, the pH is greater than 7
B) at the equivalence point, the pH is equal to 7
C) at the equivalence point, the pH is less than 7

Question 14

What is the conjugate base that is formed when carbonic acid is dissolved in water? Outcome # 3) DOK 2)

A) H₃O⁺
B) HCO₃^-
C) CO₃^2-

Question 15

Phenolphthalein can be used as an indicator in acid-base titrations. When a few drops are added to an acidic solution which is then titrated with a strong base, the color of the solution changes from _____ to _____. Outcome # 4) DOK 1)

A) colorless; pink
B) pink; colorless
C) colorless; red

Question 16

Which of the following is an amphiprotic substance? Outcome # 3) DOK 1)

A) H₃PO₄
B) PO₄^3-
C) HPO₄^2-

Question 17

Rank the following oxyanions in order of increasing basicity: ClO₄^-, ClO₂^-, ClO^-, ClO₃^-. Outcome # 3) DOK 2)

A) ClO₄^-, ClO^-, ClO₂^-, ClO₃^-
B) ClO^-, ClO₂^-, ClO₃^-, ClO₄^-
C) ClO₄^-, ClO₃^-, ClO₂^-, ClO^-

Question 18

If 3 mL of a 0.5 M HBr solution is added to 20 mL of a 0.5 M NaOH solution, the resulting solution would be _____. Outcome # 10) DOK 2) Paired item 1)

A) acidic
B) basic
C) neutral

Question 19

What is the conjugate base that is formed upon the addition of carbonic acid to water? Outcome # 3) DOK 2)

A) HCO₃^-
B) H₃O⁺
C) CO₃^2-

Question 20

Which of the following is a diprotic acid? Outcome # 3) DOK 1)

A) H₃PO₄
B) H₂PO₄^-
C) HPO₄^2-

Question 21

A student discovers a bottle of a highly corrosive monoprotic acid with the label partially destroyed. How can the concentration of the unknown acid be determined without using a pH meter? Outcome # 10) DOK 3)

A) The student can set-up a titration experiment, where a standardized NaOH solution is used to titrate the unknown strong acid. The moles of OH^- added would be equal to moles of H⁺ in the unknown at the half-way point, therefore, the concentration of the unknown can be calculated.
B) The student can set-up a titration experiment, where a standardized NaOH solution is used to titrate the unknown strong acid. The moles of OH^- added would be equal to moles of H⁺ in the unknown at the equivalence point, therefore, the concentration of the unknown can be calculated.
C) The student can set-up a titration experiment, where a standardized NaOH solution is used to titrate the unknown strong acid. The pH at the equivalence point should be 7 since this is a neutralization reaction, therefore, the concentration of the unknown acid is 1 x 10^-7 M.

Question 22

A student discovers a bottle of NaOH with a partially destroyed label. How can the concentration be determined without using a pH meter? Outcome # 10) DOK 3)

A) The student can set-up a titration experiment, where a standardized HCl solution is used to titrate the NaOH. The moles of H⁺ and OH^- are equal at the equivalence point, therefore, the concentration of NaOH can be calculated.
B) The student can set-up a titration experiment, where a standardized HCl solution is used to titrate the NaOH. The pH at the equivalence point should be 7 since this is a neutralization reaction, therefore, the concentration of NaOH is 1 x 10^-7 M.
C) The student can set-up a titration experiment, where a standardized NaOH solution is used to titrate HCl. The moles of H⁺ and OH^- are equal at the equivalence point, therefore, the concentration of NaOH can be calculated.

Question 23

What is the hydroxide ion concentration for a 23 % m/v) HNO₃ solution? Outcome # 2) DOK 3)

A) 10.35 M
B) 3.65 M
C) 2.74 x 10^-15 M

Question 24

Which acid has a higher hydrogen ion concentration? Outcome # 5) DOK 2)

A) 1.0 M HCl
B) 0.050 M HNO₃
C) 1.25 M HBr

Question 25

What instrument can be used to measure the hydrogen ion concentration in solutions? Outcome # 2) DOK 1)

A) ammeter
B) pH meter
C) potentiometer

Question 26

A student titrates 50.0 mL of an unknown concentration of HI with 85 mL of a 1.0 M solution of NaOH to reach the equivalence point. What is the pH of the HI solution? Outcome # 10) DOK 3)

A) -0.23
B) 0.23
C) 1.7

Question 27

What is the conjugate acid in the following reaction: HCl aq) + H₂O l) $\rightarrow$ Cl^- aq) + H₃O⁺ aq)?

A) Cl^-
B) H₃O⁺
C) H₂O

Question 28

What is the pH of 0.048 M solution of hydrochloric acid? Outcome # 7) DOK 1)

A) 0.32
B) 4.8
C) 1.3

Question 29

What is the hydronium concentration of a solution at pH 7? Outcome # 10) DOK 1)

A) 1 x 10⁺⁷ M
B) 1 x 10^-14 M
C) 1 x 10^-7 M

Question 30

A student titrates a 25 mL of an unknown concentration of HCl with 35 mL of a 0.890 M solution of KOH to reach the equivalence point. What is the pH of the HCl solution? Outcome # 10) DOK 3) Paired item 1)

A) -0.10
B) 0.10
C) 1.2

Question 31

What is the conjugate base in the following reaction: HCl aq) + H₂O l) $\rightarrow$ Cl^- aq) + H₃O⁺ aq)? Paired item 1)

A) Cl^-
B) H₃O⁺
C) H₂O

Question 32

What is the conjugate acid of HSO₄^-? Outcome # 5) DOK 2)

A) H₂SO₄
B) SO₄^2-
C) H₂SO₄^-

Question 33

What is the pH of 0.48 M HCl solution? Outcome # 2) DOK 1)

A) 0.32
B) -0.32
C) 13.68

Question 34

What is the conjugate base of HSO₄^-? Outcome # 5) DOK 2)

A) H₂SO₄
B) SO₄^2-
C) SO₄^-

Question 35

Blood is considered a buffered solution. What is the pH range of blood? Outcome # 2) DOK 1)

A) 7.35 - 7.45
B) 6.35 - 6.45
C) 8.35 - 8.45

Question 36

What is the pH of deionized water? Outcome # 7) DOK 1)

A) pH = 7
B) pH < 7
C) pH > 7

Question 37

What is the pH of 0.014 M solution of hydroiodic acid? Outcome # 7) DOK 1) Paired item 1)

A) 1.4
B) 1.9
C) 0.85

Question 38

What is the pH of 8.1 x 10^-5 M HClO₄ solution? Outcome # 2) DOK 1) Paired item 1)

A) 9.91
B) 4.09
C) -4.09

Question 39

What is the base in the following reaction: HCl aq) + H₂O l) $\rightarrow$ Cl^- aq) + H₃O⁺ aq)?

A) Cl^-
B) H₃O⁺
C) H₂O

Question 40

Which acid has a lower pH? Outcome # 5) DOK 2)

A) 1.0 M acetic acid
B) 0.50 M acetic acid
C) 0.25 M acetic acid

Question 41

What is the pOH of a solution that has a pH of 7? Outcome # 2) DOK 1)

A) 7
B) 14
C) 0

Question 42

What is the pOH of a solution that has a pH of 2? Outcome # 2) DOK 1) Paired item 1)

A) 12
B) 7
C) 14

Question 43

What is the conjugate base in the following reaction: HI aq) + H₂O l) $\rightarrow$ I^- aq) + H₃O⁺ aq)?

A) I^-
B) H₃O⁺
C) H₂O

Question 44

What is the acid in the following reaction: NH₃ aq) + H₂O l) $\rightarrow$ NH₄⁺ aq) + OH^- aq)?

A) NH₃
B) NH₄⁺
C) H₂O

Question 45

Write the equilibrium expression for the autoionization of water. Outcome # 3) DOK 3)

A) K_w = [H₃O⁺] [OH^-] / [H₂O]²
B) K_w = [H₃O⁺] [OH^-]
C) K_w = [H₂O]² / [H₃O⁺] [OH^-]

Question 46

Which acid has the lowest hydroxide ion concentration? Outcome # 5) DOK 2)

A) 0.010 M HCl
B) 0.050 M HNO₃
C) 0.015 M HBr