TB_Acid and Bases

Question 1

Under the Bronsted concept of acids and bases, a base is
A. a proton donor
B. a proton acceptor
C. a hydroxide donor
D. an electron pair donor

Answer 1

B. a proton acceptor

Question 2

Under the Lewis concept of acids and bases, an acid is
A. a proton donor
B. a proton acceptor
C. An electron pair donor
D. an electron pair acceptor

Answer 2

D. an electron pair acceptor

Question 3

Under the Bronsted concept of acids and bases, an acid is
A. a proton donor
B. a proton acceptor
C. an electron pair donor
D. an electron pair acceptor

Answer 3

A. a proton donor

Question 4

Which of the following is NOT an acid-base conjugate pair?
A. HCN and CN−
B. H2O and OH−
C. H2S and OH−
D. NH3 and NH4
+

Answer 4

C. H2S and OH−

Question 5

Predict the products of the following acid-base reaction:HCl(aq) + NaOH(aq) →
A. H3O+
(aq) + OH−
B. Na+
(aq) + Cl−
(aq)
C. NaCl(aq) + H2O(l)
D. no reaction takes place

Answer 5

C. NaCl(aq) + H2O(l)

Question 6

Predict the products of the following acid-base reaction: NH3(aq) + HNO3(aq) →
A. NH2OH(aq) + HNO2(aq)
B. NH4NO3(aq)
C. NH4OH(aq)
D. no reaction takes place

Answer 6

B. NH4NO3(aq)

Question 7

What effect will addition of excess of HCl have on the pH of a solution of NH3?
A. increase the pH
B. decrease the pH
C. no effect
D. cannot tell from information given

Answer 7

B. decrease the pH

Question 8

What effect will addition of sodium acetate have on the pH of a solution of acetic acid?
A. increase the pH
B. decrease the pH
C. no effect
D. cannot tell from information given

Answer 8

A. increase the pH

Question 9

A solution that causes only a relatively small change in pH upon addition of small amounts of acids and bases is
A. saturated
B. a salt
C. a buffer
D. unsaturated

Answer 9

C. a buffer

Question 10

Which of the following is buffer?
A. NaCl/NH4Cl
B. NH3/NH4Cl
C. NH3/CH3COOH
D. CH3COOH/NaOH

Answer 10

B. NH3/NH4Cl

Question 11

A buffer solution may be a mixture of
A. a weak acid and its salt
B. a weak base and its salt
C. an excess of a weak acid with a strong base
D. all of the above

Answer 11

D. all of the above

Question 12

The conjugate base of acetic acid is
A. HCOOH
B. NH3
C. CH3COO−
D. OH−

Answer 12

C. CH3COO−

Question 13

The conjugate acid of ammonia is
A. H3O+
B. NH4+
C. HCOOH
D. OH−

Answer 13

B. NH4+

Question 14

Effect produced by an ion, say from a salt, which is the same ion produced by the dissociation of a weak acid or
base is called
A. colloidal effect
B. precipitation effect
C. common ion effect
D. ligand effect

Answer 14

C. common ion effect

Question 15

A principle stating that if stress is applied to a system at equilibrium, the equilibrium is shifted in the
direction that tends to reduce the stress.
A. Heisenberg Uncertainty Principle
B. Le Chatelier’s Principle
C. Hund’s Rule
D. Debye-Huckel Principle

Answer 15

B. Le Chatelier’s Principle

Question 16

Water cannot function as which one of the following?
A. a Bronsted acid
B. a Bronsted base
C. a Lewis acid
D. a Lewis base

Answer 16

C. a Lewis acid

Question 17

HCOOK is a/an
A. acid
B. base
C. salt
D. oxide

Answer 17

C. salt

Question 18

When a strong acid is titrated with a weak base, the pH at the equivalence point is
A. basic
B. acidic
C. neutral
D. none of the above

Answer 18

B. acidic

Question 19

When a strong acid is titrated with a strong base, the pH at the equivalence point is
A. basic
B. acidic
C. neutral
D. none of the above

Answer 19

C. neutral

Question 20

When NH4Cl hydrolyzes, the resulting solution is
A. acidic
B. basic
C. neutral
D. none of the above

Answer 20

A. acidic

Question 21

We have a 5.43 x 10−4 M solution of HNO3 at 25oC. What is the [OH−
] in this solution?
A. 1.84 x 10−11 M
B. 5.43 x 10−10 M
C. 5.43 x 10−4 M
D. 3.67 x 10−6 M

Answer 21

A. 1.84 x 10−11 M

Question 22

What is the pH of a 5.82 x 10−3 M solution of NaOH at 25oC?
A. 4.76
B. 11.76
C. 7.00
D. 2.45

Answer 22

B. 11.76

Question 23

The pH of a 0.20 M NH3 solution is Kb (NH3) = 1.8 x 10‒5
A. 0.70
B. 2.73
C. 11.28
D. 6.99

Answer 23

C. 11.28

Question 24

The pH of a solution is 6.38. The hydrogen ion concentration is
A. 4.17 x 10−7 M
B. 4.17 x 10−6 M
C. 6.38 x 10−6 M
D. 0.638 M

Answer 24

A. 4.17 x 10−7 M

Question 25

What is the [H3O+ ] of a 0.100 M solution of HCN at 25oC? Ka (HCN) = 4.0 x 10−10 A. 1.58 x 10−8 M B. 2.00 x 10−5 M C. 6.32 x 10−6 M D. 4.00 x 10−11 M

Answer 25

C. 6.32 x 10−6 M

Question 26

A 0.200 M solution of an acid, HA, has a pH of 2.70 at 25oC. What is Ka for this acid? A. 2.21 x 10−4 B. 4.55 x 10−6 C. 1.99 x 10−4 D. 2.00 x 10−5

Answer 26

D. 2.00 x 10−5

Question 27

What is the pH of a 0.52 M solution of CH3COONa at 25oC? Ka (CH3COOH) = 1.76 x 10−5 A. 9.23 B. 4.77 C. 9.37 D. 10.21

Answer 27

A. 9.23

Question 28

Acids and Bases Which statement is true? a. The value of the equilibrium constant increases with the addition of a catalyst b. A catalyst speeds up both the forward and reverse reaction rates c. The greater the activation energy, the faster the rate of reaction. d. A catalyst increases the rate of reaction by decreasing the number of collisions

Answer 28

b. A catalyst speeds up both the forward and reverse reaction rates

Question 29

The lining of the stomach contains cells that secrete a solution of HCl. Which drink would best alleviate heartburn (excess acid in the stomach)? a. milk, pH = 6.5 b. wine, pH = 3.8 c. diet soda, pH = 4.3 d. milk of magnesia, pH = 10.5

Answer 29

d. milk of magnesia, pH = 10.5

Question 30

Which species are acting as Bronsted acids in the reaction below? HSO4 − (aq) + H2O(l) ⇄ H3O+ (aq) + SO4 −2(aq) a. H2O b. H2O and H3O+ c. H2O and SO4−2 d. HSO4− and H3O+

Answer 30

d. HSO4− and H3O+

Question 31

Which equation correctly describes the relationship between Kb and Ka for a conjugate acid/base pair? a. Kb = Kw Ka b. Kb = Ka / Kw c. Kb = Kw / Ka d. Kb = Ka + Kw

Answer 31

c. Kb = Kw / Ka