Question 1

Calculate the pOH of a 0.12 M solution of acetic acid (Ka = 1.8 $\times$ 10-5).

Accepted Answer

A) 2.83 
B) 8.33 
C) 5.67 
D) 11.17 
E) 1.91 
A) 2.83 
B) 8.33 
C) 5.67 
D) 11.17 
E) 1.91

Question 2

Calculate the pH of a 0.13 M solution of HOCl,Ka = 3.5 $\times$ 10-8.

Accepted Answer

A) 4.17 
B) 8.34 
C) 9.83 
D) 1.00 
E) 3.76 
A) 4.17 
B) 8.34 
C) 9.83 
D) 1.00 
E) 3.76

Question 3

The equilibrium constant for the reaction NH4+ + OH-   NH3 + H2O is:

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 4

The following question refers to a solution that contains 1.99 M hydrofluoric acid,HF (Ka = 7.2 $\times$ 10-4),and 3.00 M hydrocyanic acid,HCN (Ka = 6.2 $\times$10-10). Determine the [CN-] at equilibrium.

Accepted Answer

A) 1.9 $\times$ 10-9 M 
B) 3.8 $\times$10-2 M 
C) 4.9 $\times$ 10-8 M 
D) 6.2 $\times$ 10-10 M 
E) none of these 
A) 1.9 $\times$ 10-9 M 
B) 3.8 $\times$10-2 M 
C) 4.9 $\times$ 10-8 M 
D) 6.2 $\times$ 10-10 M 
E) none of these

Question 5

Calculate the pH of the following aqueous solution: 0.35 M NaF (pKa for HF = 3.14)

Accepted Answer

A) 5.66 
B) 2.68 
C) 8.34 
D) 11.32 
E) none of these 
A) 5.66 
B) 2.68 
C) 8.34 
D) 11.32 
E) none of these

Question 6

What is the equilibrium concentration of HPO42- in a 0.528 M solution of H3PO4(aq)? (Ka1 = 7.5 $\times$ 10-3,Ka2 = 6.2 $\times$ 10-8,Ka3 = 4.8 $\times$10-13)

Accepted Answer

A) 1.8 $\times$ 10-4 M 
B) 5.9 $\times$10-2 M 
C) 4.8 $\times$10-13 M 
D) 6.2 $\times$ 10-8 M 
E) 5.0 $\times$ 10-7 M 
A) 1.8 $\times$ 10-4 M 
B) 5.9 $\times$10-2 M 
C) 4.8 $\times$10-13 M 
D) 6.2 $\times$ 10-8 M 
E) 5.0 $\times$ 10-7 M

Question 7

Consider a 0.70 M solution of HOCl.If the molarity was decreased to 0.3 M,which of the following statements would be true?

Accepted Answer

A) The percent dissociation would not change. 
B) The percent dissociation would increase. 
C) The percent dissociation would decrease. 
D) The equilibrium constant would stay the same. 
E) Two of these. 
A) The percent dissociation would not change. 
B) The percent dissociation would increase. 
C) The percent dissociation would decrease. 
D) The equilibrium constant would stay the same. 
E) Two of these.

Question 8

Hypobromous acid,HOBr,has an acid dissociation constant of 2.5 $\times$10-9 at 25°C.What is the pOH of a 0.075 M HOBr solution?

Accepted Answer

A) 2.80 
B) 4.27 
C) 4.86 
D) 9.14 
E) 11.20 
A) 2.80 
B) 4.27 
C) 4.86 
D) 9.14 
E) 11.20

Question 9

Calculate the pH of the following aqueous solution: 0.5 M H2CO3 (pKa1 = 6.37;pKa2 = 10.25).Choose your answer from the following pH ranges:

Accepted Answer

A) pH 0.00-2.99 
B) pH 3.00-5.99 
C) pH 6.00-8.99 
D) pH 9.00 -10.99 
E) pH 11.00-14.00 
A) pH 0.00-2.99 
B) pH 3.00-5.99 
C) pH 6.00-8.99 
D) pH 9.00 -10.99 
E) pH 11.00-14.00

Question 10

Approximately how much water should be added to 10.0 mL of 11.1 M HCl so that it has the same pH as 0.90 M acetic acid (Ka = 1.8 $\times$ 10-5)?

Accepted Answer

A) 28 mL 
B) 276 mL 
C) 3 L 
D) 28 L 
E) 276 L 
A) 28 mL 
B) 276 mL 
C) 3 L 
D) 28 L 
E) 276 L

Question 11

Which of the following would give the highest pH when dissolved in water to form a 0.10 M solution?

Accepted Answer

A) a strong acid 
B) a weak acid 
C) the potassium salt of a weak acid 
D) the potassium salt of a strong acid 
E) the ammonium salt of a strong acid 
A) a strong acid 
B) a weak acid 
C) the potassium salt of a weak acid 
D) the potassium salt of a strong acid 
E) the ammonium salt of a strong acid

Question 12

A 0.33-mol sample of a diprotic acid,H2A,is dissolved in 250 mL of water.The Ka1 of this acid is 1.0 $\times$ 10-5 and Ka2 is 1.0 $\times$ 10-10.Calculate the concentration of A2- in this solution.

Accepted Answer

A) 1.0 $\times$10-5 M 
B) 1.8 $\times$ 10-3 M 
C) 3.6 $\times$10-3 M 
D) 1.0 $\times$ 10-10 M 
E) 1.32 M 
A) 1.0 $\times$10-5 M 
B) 1.8 $\times$ 10-3 M 
C) 3.6 $\times$10-3 M 
D) 1.0 $\times$ 10-10 M 
E) 1.32 M

Question 13

Which is the strongest acid of the following?

Accepted Answer

A) HClO2 
B) HClO 
C) HBrO 
D) HIO 
E) HOAt 
A) HClO2 
B) HClO 
C) HBrO 
D) HIO 
E) HOAt

Question 14

Saccharin is a monoprotic acid.If the pH of a 4.41 $\times$ 10-3 M solution of this acid is 2.53,what is the Ka of saccharin?

Accepted Answer

A) 8.7 $\times$ 10-6 
B) 2.0 $\times$ 10-3 
C) 6.0 $\times$ 10-3 
D) 2.9 $\times$ 10-3 
E) none of these 
A) 8.7 $\times$ 10-6 
B) 2.0 $\times$ 10-3 
C) 6.0 $\times$ 10-3 
D) 2.9 $\times$ 10-3 
E) none of these

Question 15

Which of the following solutions contains the strongest acid?

Accepted Answer

A) 5.00 M HCN (Ka = 6.2 $\times$ 10-10) 
B) 3.50 M H2C6H6O6 (Ka1 = 7.9 $\times$10-5,Ka2 = 1.6 $\times$ 10-12). 
C) 2.50 M HC2H3O2 (Ka = 1.8 $\times$ 10-5) 
D) 4.00 M HOCl (Ka = 3.5 $\times$ 10-8) 
E) 1.00 M HF (Ka = 7.2 $\times$ 10-4) 
A) 5.00 M HCN (Ka = 6.2 $\times$ 10-10) 
B) 3.50 M H2C6H6O6 (Ka1 = 7.9 $\times$10-5,Ka2 = 1.6 $\times$ 10-12). 
C) 2.50 M HC2H3O2 (Ka = 1.8 $\times$ 10-5) 
D) 4.00 M HOCl (Ka = 3.5 $\times$ 10-8) 
E) 1.00 M HF (Ka = 7.2 $\times$ 10-4)

Question 16

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 acid.

Accepted Answer

A) HCN 
B) HNO3 
C) H2O 
D) OH- 
E) CH3OH 
A) HCN 
B) HNO3 
C) H2O 
D) OH- 
E) CH3OH

Question 17

If Ka for HCN is 6.17 $\times$ 10-10,what is Kb for CN-? Note: CN- + H2O   HCN + OH-

Accepted Answer

A) 6.17 $\times$ 10-24 
B) 6.17 $\times$ 104 
C) 1.62 $\times$ 10-5 
D) 1.23 $\times$ 10-9 
E) none of these 
A) 6.17 $\times$ 10-24 
B) 6.17 $\times$ 104 
C) 1.62 $\times$ 10-5 
D) 1.23 $\times$ 10-9 
E) none of these

Question 18

The pH of a 0.17 M solution of a weak monoprotic acid,HA,is 2.92.Calculate the Ka for this acid.

Accepted Answer

A) 0.17 
B) 1.2 $\times$ 10-3 
C) 7.1 $\times$ 10-3 
D) 8.6 $\times$ 10-6 
E) 7.3 $\times$ 10-11 
A) 0.17 
B) 1.2 $\times$ 10-3 
C) 7.1 $\times$ 10-3 
D) 8.6 $\times$ 10-6 
E) 7.3 $\times$ 10-11

Question 19

Calculate the pH of a 0.47 M NH3 (Kb = 1.8$\times$ 10-5)solution.

Accepted Answer

A) 2.54 
B) 8.93 
C) 5.07 
D) 0.47 
E) 11.46 
A) 2.54 
B) 8.93 
C) 5.07 
D) 0.47 
E) 11.46

Question 20

Calculate the [H+] in a solution that has a pH of 2.73.

Accepted Answer

A) 2.7 M 
B) 11.3 M 
C) 1.9 $\times$ 10-3 M 
D) 5.4 $\times$ 10-12 M 
E) none of these 
A) 2.7 M 
B) 11.3 M 
C) 1.9 $\times$ 10-3 M 
D) 5.4 $\times$ 10-12 M 
E) none of these

Exam 14: Acids and Bases

Calculate the pOH of a 0.12 M solution of acetic acid (Ka = 1.8 ×\times× 10-5).

Calculate the pH of a 0.13 M solution of HOCl,Ka = 3.5 ×\times× 10-8.

The equilibrium constant for the reaction NH4+ + OH- NH3 + H2O is:

The following question refers to a solution that contains 1.99 M hydrofluoric acid,HF (Ka = 7.2 ×\times× 10-4),and 3.00 M hydrocyanic acid,HCN (Ka = 6.2 ×\times× 10-10). Determine the [CN-] at equilibrium.

Calculate the pH of the following aqueous solution: 0.35 M NaF (pKa for HF = 3.14)

What is the equilibrium concentration of HPO42- in a 0.528 M solution of H3PO4(aq)? (Ka1 = 7.5 ×\times× 10-3,Ka2 = 6.2 ×\times× 10-8,Ka3 = 4.8 ×\times× 10-13)

Consider a 0.70 M solution of HOCl.If the molarity was decreased to 0.3 M,which of the following statements would be true?

Hypobromous acid,HOBr,has an acid dissociation constant of 2.5 ×\times× 10-9 at 25°C.What is the pOH of a 0.075 M HOBr solution?

Calculate the pH of the following aqueous solution: 0.5 M H2CO3 (pKa1 = 6.37;pKa2 = 10.25).Choose your answer from the following pH ranges:

Approximately how much water should be added to 10.0 mL of 11.1 M HCl so that it has the same pH as 0.90 M acetic acid (Ka = 1.8 ×\times× 10-5)?

Which of the following would give the highest pH when dissolved in water to form a 0.10 M solution?

A 0.33-mol sample of a diprotic acid,H2A,is dissolved in 250 mL of water.The Ka1 of this acid is 1.0 ×\times× 10-5 and Ka2 is 1.0 ×\times× 10-10.Calculate the concentration of A2- in this solution.

Which is the strongest acid of the following?

Saccharin is a monoprotic acid.If the pH of a 4.41 ×\times× 10-3 M solution of this acid is 2.53,what is the Ka of saccharin?

Which of the following solutions contains the strongest acid?

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 acid.

If Ka for HCN is 6.17 ×\times× 10-10,what is Kb for CN-? Note: CN- + H2O HCN + OH-

The pH of a 0.17 M solution of a weak monoprotic acid,HA,is 2.92.Calculate the Ka for this acid.

Calculate the pH of a 0.47 M NH3 (Kb = 1.8 ×\times× 10-5)solution.

Calculate the [H+] in a solution that has a pH of 2.73.

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Filters

Calculate the pOH of a 0.12 M solution of acetic acid (K_a = 1.8 $\times$ 10^-⁵).

Calculate the pH of a 0.13 M solution of HOCl,K_a = 3.5 $\times$ 10^-⁸.

The equilibrium constant for the reaction NH₄⁺ + OH^- NH₃ + H₂O is:

The following question refers to a solution that contains 1.99 M hydrofluoric acid,HF (K_a = 7.2 $\times$ 10^-⁴),and 3.00 M hydrocyanic acid,HCN (K_a = 6.2 $\times$ 10^-¹⁰). Determine the [CN^-] at equilibrium.

Calculate the pH of the following aqueous solution: 0.35 M NaF (pK_a for HF = 3.14)

What is the equilibrium concentration of HPO₄²^- in a 0.528 M solution of H₃PO₄(aq)? (K_a1 = 7.5 $\times$ 10^-³,K_a2 = 6.2 $\times$ 10^-⁸,K_a3 = 4.8 $\times$ 10^-¹³)

Hypobromous acid,HOBr,has an acid dissociation constant of 2.5 $\times$ 10^-⁹ at 25°C.What is the pOH of a 0.075 M HOBr solution?

Calculate the pH of the following aqueous solution: 0.5 M H₂CO₃ (pK_a1 = 6.37;pK_a2 = 10.25).Choose your answer from the following pH ranges:

Approximately how much water should be added to 10.0 mL of 11.1 M HCl so that it has the same pH as 0.90 M acetic acid (K_a = 1.8 $\times$ 10^-⁵)?

A 0.33-mol sample of a diprotic acid,H₂A,is dissolved in 250 mL of water.The K_a1of this acid is 1.0 $\times$ 10^-⁵ and K_a2is 1.0 $\times$ 10^-¹⁰.Calculate the concentration of A²^- in this solution.

Saccharin is a monoprotic acid.If the pH of a 4.41 $\times$ 10^-³M solution of this acid is 2.53,what is the K_a of saccharin?

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 acid.

The pH of a 0.17 M solution of a weak monoprotic acid,HA,is 2.92.Calculate the K_a for this acid.

Calculate the pH of a 0.47 M NH₃ (K_b = 1.8 $\times$ 10^-⁵)solution.

Calculate the [H⁺] in a solution that has a pH of 2.73.