Question 1

Calculate the pH of a 0.69 M solution of pyridine (C5H5N;Kb = 1.7 $\times$ 10-9):

Accepted Answer

A) 4.47 
B) 5.07 
C) 9.53 
D) 8.93 
E) none of these 
A) 4.47 
B) 5.07 
C) 9.53 
D) 8.93 
E) none of these

Question 2

Select the answer that best describes an aqueous solution made from each of the following substances:
-solid ammonium perchlorate (NH4ClO4)For NH4+,Ka = 5.6 $\times$ 10-10;for ClO4-,Kb $\times$ 10-21.

Accepted Answer

A) acidic 
B) basic 
C) neutral 
D) cannot tell 
E) none of these (A-
D)  
A) acidic 
B) basic 
C) neutral 
D) cannot tell 
E) none of these (A-
D)

Question 3

Determine whether the following oxides produce an acidic,basic,or neutral solution when dissolved in water:
-SO2

Accepted Answer

acidic SO₂(g)+ H

Question 4

Which factor listed below is most important in determining the strength of an oxyacid?

Accepted Answer

A) the size of the molecule 
B) the ability of the molecule to change atomic orientation 
C) the identity of the central atom in the molecule 
D) the number of oxygen atoms present in the molecule 
E) none of these 
A) the size of the molecule 
B) the ability of the molecule to change atomic orientation 
C) the identity of the central atom in the molecule 
D) the number of oxygen atoms present in the molecule 
E) none of these

Question 5

Assuming that the value for K in the above reaction is greater than 1,this means that HF is a stronger acid than HOCl.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following reactions is associated with the definition of Kb?

Accepted Answer

A) Zn(OH2)62+   [Zn(OH2)5OH]+ + H+ 
B) CN- + H+   HCN 
C) F- + H2O   HF + OH- 
D) Cr3+ + 6H2O   Cr(OH2)63+ 
E) none of these 
A) Zn(OH2)62+   [Zn(OH2)5OH]+ + H+ 
B) CN- + H+   HCN 
C) F- + H2O   HF + OH- 
D) Cr3+ + 6H2O   Cr(OH2)63+ 
E) none of these

Question 7

Solid calcium hydroxide is dissolved in water until the pH of the solution is 11.44.The hydroxide ion concentration [OH-] of the solution is:

Accepted Answer

A) 3.6 $\times$ 10-12 M 
B) 5.5 $\times$ 10-3 M 
C) 2.8 $\times$ 10-3 M 
D) 1.4 $\times$ 10-3 M 
E) none of these 
A) 3.6 $\times$ 10-12 M 
B) 5.5 $\times$ 10-3 M 
C) 2.8 $\times$ 10-3 M 
D) 1.4 $\times$ 10-3 M 
E) none of these

Question 8

For weak acid,HX,Ka = 6.9 $\times$ 10-6.Calculate the pH of a 0.13 M solution of HX.

Accepted Answer

A) 0.89 
B) 3.02 
C) 6.05 
D) 10.98 
E) none of these 
A) 0.89 
B) 3.02 
C) 6.05 
D) 10.98 
E) none of these

Question 9

Determine the concentration of a solution of the weak acid HClO2 (Ka = 1.10 $\times$ 10-2)if it has a pH of 1.075.

Accepted Answer

A) 0.644 M 
B) 0.0841 M 
C) 7.65 M 
D) 12.9 M 
E) 1.287 M 
A) 0.644 M 
B) 0.0841 M 
C) 7.65 M 
D) 12.9 M 
E) 1.287 M

Question 10

Which of the following species is present in the greatest concentration in a 0.100 M H2SO4 solution in H2O?

Accepted Answer

A) H3O+ 
B) HSO4- 
C) H2SO4 
D) All species are in equilibrium and therefore have the same concentration. 
E) SO42- 
A) H3O+ 
B) HSO4- 
C) H2SO4 
D) All species are in equilibrium and therefore have the same concentration. 
E) SO42-

Question 11

The following three equations represent equilibria that lie far to the right.
HNOS1U1B13S1U1B0(aq)+ CNS1U1P1-S1S1P0(aq)   HCN(aq)+ NOS1U1B13S1U1B0S1U1P1-S1S1P0(aq)
HCN(aq)+ OHS1U1P1-S1S1P0(aq)   HS1U1B12S1U1B0O(l)+ CNS1U1P1-S1S1P0(aq)
HS1U1B12S1U1B0O(l)+ CHS1U1B13S1U1B0OS1U1P1-S1S1P0(aq)   CHS1U1B13S1U1B0OH(aq)+ OHS1U1P1-S1S1P0(aq)
-Identify the strongest base.

Accepted Answer

A) CH3O- 
B) CH3OH 
C) CN- 
D) H2O 
E) NO3- 
A) CH3O- 
B) CH3OH 
C) CN- 
D) H2O 
E) NO3-

Question 12

The conjugate acid and conjugate base of bicarbonate ion,HCO3-,are,respectively:

Accepted Answer

A) H3O+ and OH- 
B) H3O+ and CO32- 
C) H2CO3 and OH- 
D) H2CO3 and CO32- 
E) CO32- and OH- 
A) H3O+ and OH- 
B) H3O+ and CO32- 
C) H2CO3 and OH- 
D) H2CO3 and CO32- 
E) CO32- and OH-

Question 13

Calculate the pH of a 0.04 M solution of ascorbic acid (Ka1 = 7.9 $\times$10-5;Ka2 is 1.6 $\times$10-12).

Accepted Answer

A) 11.2 
B) 2.8 
C) 5.5 
D) 8.5 
E) 11.8 
A) 11.2 
B) 2.8 
C) 5.5 
D) 8.5 
E) 11.8

Question 14

HA and HB are both weak acids in water,and HA is a stronger acid than HB.Which of the following statements is correct?

Accepted Answer

A) A- is a stronger base than B-,which is a stronger base than H2O,which is a stronger base than Cl-. 
B) B- is a stronger base than A-,which is a stronger base than H2O,which is a stronger base than Cl-. 
C) B- is a stronger base than A-,which is a stronger base than Cl-,which is a stronger base than H2O. 
D) Cl- is a stronger base than A-,which is a stronger base than B-,which is a stronger base than H2O. 
E) None of these (A-
D) is correct. 
A) A- is a stronger base than B-,which is a stronger base than H2O,which is a stronger base than Cl-. 
B) B- is a stronger base than A-,which is a stronger base than H2O,which is a stronger base than Cl-. 
C) B- is a stronger base than A-,which is a stronger base than Cl-,which is a stronger base than H2O. 
D) Cl- is a stronger base than A-,which is a stronger base than B-,which is a stronger base than H2O. 
E) None of these (A-
D) is correct.

Question 15

Select the answer that best describes an aqueous solution made from each of the following substances:
-solid sodium carbonate (Na2CO3)

Accepted Answer

A) acidic 
B) basic 
C) neutral 
D) cannot tell 
E) none of these (A-
D)  
A) acidic 
B) basic 
C) neutral 
D) cannot tell 
E) none of these (A-
D)

Question 16

Calculate the pH of the following aqueous solution: 0.62 M H2S (pKa1 = 7.00;pKa2 = 12.89)

Accepted Answer

A) 10.40 
B) 3.60 
C) 7.21 
D) 6.79 
E) none of these 
A) 10.40 
B) 3.60 
C) 7.21 
D) 6.79 
E) none of these

Question 17

The autoionization of water,as represented by the below equation,is known to be endothermic.Which of the following correctly states what occurs as the temperature of water is raised? H2O(l)+ H2O(l)   H3O+(aq)+ OH-(aq)

Accepted Answer

A) The pH of the water does not change,and the water remains neutral. 
B) The pH of the water decreases,and the water becomes more acidic. 
C) The pH of the water decreases,and the water remains neutral. 
D) The pH of the water increases,and the water becomes more acidic. 
E) The pH of the water increases and the water remains neutral. 
A) The pH of the water does not change,and the water remains neutral. 
B) The pH of the water decreases,and the water becomes more acidic. 
C) The pH of the water decreases,and the water remains neutral. 
D) The pH of the water increases,and the water becomes more acidic. 
E) The pH of the water increases and the water remains neutral.

Question 18

Which of the following is not true for a solution at 25°C that has a hydroxide concentration of 2.5 $\times$ 10-6 M?

Accepted Answer

A) Kw = 1 $\times$ 10-14 
B) The solution is acidic. 
C) The solution is basic. 
D) The [H+] is 4.0 $\times$ 10-9 M. 
E) The Kw is independent of what the solution contains. 
A) Kw = 1 $\times$ 10-14 
B) The solution is acidic. 
C) The solution is basic. 
D) The [H+] is 4.0 $\times$ 10-9 M. 
E) The Kw is independent of what the solution contains.

Question 19

Calculate the pH of a 2.28 M solution of NaOH.

Accepted Answer

A) 0.358 
B) 13.642 
C) 14.358 
D) 2.28 
E) none of these 
A) 0.358 
B) 13.642 
C) 14.358 
D) 2.28 
E) none of these

Question 20

Calculate the percentage of pyridine (C5H5N)that forms pyridinium ion,C5H6N+,in a 0.72 M aqueous solution of pyridine (Kb = 1.7 $\times$10-9).

Accepted Answer

A) 1.7 $\times$ 10-7 % 
B) 3.5 $\times$ 10-3 % 
C) 2.4 $\times$ 10-7 % 
D) 6.7 $\times$10-3 % 
E) 4.9 $\times$ 10-3 % 
A) 1.7 $\times$ 10-7 % 
B) 3.5 $\times$ 10-3 % 
C) 2.4 $\times$ 10-7 % 
D) 6.7 $\times$10-3 % 
E) 4.9 $\times$ 10-3 %

Exam 14: Acids and Bases

Calculate the pH of a 0.69 M solution of pyridine (C5H5N;Kb = 1.7 ×\times× 10-9):

Select the answer that best describes an aqueous solution made from each of the following substances: -solid ammonium perchlorate (NH4ClO4)For NH4+,Ka = 5.6 ×\times× 10-10;for ClO4-,Kb ×\times× 10-21.

Determine whether the following oxides produce an acidic,basic,or neutral solution when dissolved in water: -SO2

Which factor listed below is most important in determining the strength of an oxyacid?

Assuming that the value for K in the above reaction is greater than 1,this means that HF is a stronger acid than HOCl.

Which of the following reactions is associated with the definition of Kb?

Solid calcium hydroxide is dissolved in water until the pH of the solution is 11.44.The hydroxide ion concentration [OH-] of the solution is:

For weak acid,HX,Ka = 6.9 ×\times× 10-6.Calculate the pH of a 0.13 M solution of HX.

Determine the concentration of a solution of the weak acid HClO2 (Ka = 1.10 ×\times× 10-2)if it has a pH of 1.075.

Which of the following species is present in the greatest concentration in a 0.100 M H2SO4 solution in H2O?

The following three equations represent equilibria that lie far to the right. HNO3(aq)+ CN-(aq) HCN(aq)+ NO3-(aq) HCN(aq)+ OH-(aq) H2O(l)+ CN-(aq) H2O(l)+ CH3O-(aq) CH3OH(aq)+ OH-(aq) -Identify the strongest base.

The conjugate acid and conjugate base of bicarbonate ion,HCO3-,are,respectively:

Calculate the pH of a 0.04 M solution of ascorbic acid (Ka1 = 7.9 ×\times× 10-5;Ka2 is 1.6 ×\times× 10-12).

HA and HB are both weak acids in water,and HA is a stronger acid than HB.Which of the following statements is correct?

Select the answer that best describes an aqueous solution made from each of the following substances: -solid sodium carbonate (Na2CO3)

Calculate the pH of the following aqueous solution: 0.62 M H2S (pKa1 = 7.00;pKa2 = 12.89)

The autoionization of water,as represented by the below equation,is known to be endothermic.Which of the following correctly states what occurs as the temperature of water is raised? H2O(l)+ H2O(l) H3O+(aq)+ OH-(aq)

Which of the following is not true for a solution at 25°C that has a hydroxide concentration of 2.5 ×\times× 10-6 M?

Calculate the pH of a 2.28 M solution of NaOH.

Calculate the percentage of pyridine (C5H5N)that forms pyridinium ion,C5H6N+,in a 0.72 M aqueous solution of pyridine (Kb = 1.7 ×\times× 10-9).

Chemical Foundations

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Filters

Calculate the pH of a 0.69 M solution of pyridine (C₅H₅N;K_b = 1.7 $\times$ 10^-⁹):

Select the answer that best describes an aqueous solution made from each of the following substances: -solid ammonium perchlorate (NH₄ClO₄)For NH₄⁺,K_a = 5.6 $\times$ 10^-¹⁰;for ClO₄^-,K_b $\times$ 10^-²¹.

Determine whether the following oxides produce an acidic,basic,or neutral solution when dissolved in water: -SO₂

Which of the following reactions is associated with the definition of K_b?

Solid calcium hydroxide is dissolved in water until the pH of the solution is 11.44.The hydroxide ion concentration [OH^-] of the solution is:

For weak acid,HX,K_a = 6.9 $\times$ 10^-⁶.Calculate the pH of a 0.13 M solution of HX.

Determine the concentration of a solution of the weak acid HClO₂ (K_a = 1.10 $\times$ 10^-²)if it has a pH of 1.075.

Which of the following species is present in the greatest concentration in a 0.100 M H₂SO₄ solution in H₂O?

The following three equations represent equilibria that lie far to the right. HNO₃(aq)+ CN^-(aq) HCN(aq)+ NO₃^-(aq) HCN(aq)+ OH^-(aq) H₂O(l)+ CN^-(aq) H₂O(l)+ CH₃O^-(aq) CH₃OH(aq)+ OH^-(aq) -Identify the strongest base.

The conjugate acid and conjugate base of bicarbonate ion,HCO₃^-,are,respectively:

Calculate the pH of a 0.04 M solution of ascorbic acid (K_a1= 7.9 $\times$ 10^-⁵;K_a2is 1.6 $\times$ 10^-¹²).

Select the answer that best describes an aqueous solution made from each of the following substances: -solid sodium carbonate (Na₂CO₃)

Calculate the pH of the following aqueous solution: 0.62 M H₂S (pK_a1 = 7.00;pK_a2 = 12.89)

The autoionization of water,as represented by the below equation,is known to be endothermic.Which of the following correctly states what occurs as the temperature of water is raised? H₂O(l)+ H₂O(l) H₃O⁺(aq)+ OH^-(aq)

Which of the following is not true for a solution at 25°C that has a hydroxide concentration of 2.5 $\times$ 10^-⁶ M?

Calculate the percentage of pyridine (C₅H₅N)that forms pyridinium ion,C₅H₆N⁺,in a 0.72 M aqueous solution of pyridine (K_b = 1.7 $\times$ 10^-⁹).