Question 1

Which of the following is the conjugate base of HPO42−?

Accepted Answer

A)  H3PO4 
B)  H2PO4− 
C)  PO43− 
D)  OH−

Question 2

Which of the following is the Brønsted-Lowry definition of a base?

Accepted Answer

A)  a hydroxide ion acceptor 
B)  a proton acceptor 
C)  a proton donor 
D)  none of these

Question 3

Which of the following species is not present in the solution when solid sodium hydroxide is dissolved in water?

Accepted Answer

A)  H2O(l) 
B)  Na+(aq) 
C)  OH−(aq) 
D)  None, they are all present.

Question 4

Which of the following can be characterized as a strong electrolyte?

Accepted Answer

A)  0.001 M HCl 
B)  3.0 M HCl 
C)  both 0.001 M HCI and 3.0 M HCI 
D)  neither 0.001 M HCI or 3.0 M HCI

Question 5

Which of the following is the net ionic equation for the reaction of the strong acid HCl with the strong base NaOH?

Accepted Answer

A)  H3O+(aq) + Cl−(aq) + Na+(aq) + OH−(aq) → Na+(aq) + Cl−(aq) + 2H2O(l) 
B)  HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) 
C)  H3O+(aq) + OH−(aq) → 2H2O(l) 
D)  none of these

Question 6

In an aqueous solution, [OH−] is 2.0 × 10−6 M. What is [H+]?

Accepted Answer

A)  5.0 × 10−9 M 
B)  1.0 × 10−7 M 
C)  2.0 × 10−6 M 
D)  1.0 × 108 M

Question 7

Which of the following occurs when an acid reacts with an active metal?

Accepted Answer

A)  The metal is oxidized. 
B)  H+ is reduced. 
C)  The metal is oxidized and H+ is reduced. 
D)  None of these.

Question 8

Which of the following is true about buffers such as HEPES, TRIS, and MOPS?

Accepted Answer

A)  The Henderson-Hasselbalch equation applies to them. 
B)  They consist of simple weak acids and bases. 
C)  They are less resistant to changes in temperature than are other buffers. 
D)  We can use them interchangeably because they all have the same pKa.

Question 9

Which of the following statements best describes the acid-base relationship?

Accepted Answer

A)  As acid strengths decrease, conjugate base strengths increase. 
B)  As base strengths decrease, conjugate acid strengths decrease. 
C)  As acid strengths decrease, conjugate base strengths increase and conjugate acid strengths decrease. 
D)  None of these.

Question 10

A solution has a pH of 7.4. What is its pOH?

Accepted Answer

A)  -6.6 
B)  -7.4 
C)  7.4 
D)  6.6

Question 11

What do buffers consist of?

Accepted Answer

A)  equal molar amounts of a weak acid and a salt of the weak acid 
B)  equal amounts of a strong acid and a salt of the strong acid 
C)  equal molar amounts of a strong base and a salt of the strong base 
D)  equal amounts of a strong acid and a strong base

Question 12

Hydrofluoric acid, HF, is a weak acid. Which of the following is the correct expression for the Ka of hydrofluoric acid?

Accepted Answer

A)  [H3O+][HF]/[F−] 
B)  [HF]/[ H3O+][F−] 
C)  [H3O+][F−]/[HF] 
D)  [HF][F−]/[ H3O+]

Question 13

How many protons can be lost by acetic acid, CH3COOH?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4

Question 14

Which of the following occurs when hydrogen chloride gas is dissolved in water to form hydrochloric acid?

Accepted Answer

A)  H2O+(aq) and O2− (aq) are formed. 
B)  H3O+(aq) and Cl−(aq) are formed. 
C)  H+(aq) and OH−(aq) are formed. 
D)  There is no reaction, and HCl molecules remain unchanged.

Question 15

The Ka of boric acid is 7.3 × 10−10. What is the pKa of boric acid?

Accepted Answer

A)  −9.14 
B)  −4.86 
C)  4.86 
D)  9.14

Question 16

Which of the following solutions can function as a buffer?

Accepted Answer

A)  a solution containing HCl and NaCl 
B)  a solution containing NaOH and NaCl 
C)  a solution containing HC2H3O2 and NaC2H3O2 
D)  all of these

Question 17

Which of the following is a diprotic acid?

Accepted Answer

A)  HCl 
B)  HNO3 
C)  H2SO4 
D)  H3PO4

Question 18

Which factor(s) do we use to determine the stronger acid when comparing the strengths of two weak acids?

Accepted Answer

A)  the values of the acid dissociation constant 
B)  the pKa values of the acids 
C)  the values of the acid dissociation constant and the pKa values of the acids 
D)  none of these

Exam 8: Acids and Bases

Which of the following is the conjugate base of HPO₄²⁻?