Question 1

What is the pH of the buffer that results when 32 g sodium acetate (NaCH3CO2)is mixed with 500.0 mL of 1.0 M acetic acid (CH3CO2H)and diluted with water to 1.0 L? (Ka of CH3CO2H = 1.8 × 10-5)

Accepted Answer

A)  2.52 
B)  4.23 
C)  4.44 
D)  4.64 
E)  4.74

Question 2

What molar ratio of acetic acid to sodium acetate is required to create a buffer solution having a pH of 4.88 at 25°C? Ka for HC2H3O2 is 1.8 × 10-5.

Accepted Answer

A)  0.73 
B)  1.4 
C)  0.52 
D)  2.0 
E)  2.7

Question 3

What mass of sodium hydroxide must be added to 65.0 mL of 0.926 M acetic acid in order to create a buffer with a pH of 4.83? Ka for acetic acid is 1.8 × 10-5.

Accepted Answer

A)  49 g 
B)  1.3 g 
C)  1.0 g 
D)  0 g 
E)  2.4 g

Question 4

Suppose 50.00 mL of 2.0 × 10-5 M Fe(NO3)3 is added to 50.00 mL of 2.0 ×10-4 M KIO3.Which of the following statements is true? For Fe(IO3)3,Ksp = 1.0 × 10-14.

Accepted Answer

A)  A precipitate forms because Qc > Ksp. 
B)  A precipitate forms because Qc sp. 
C)  No precipitate forms because Qc sp. 
D)  No precipitate forms because Qc = Ksp. 
E)  No precipitate forms because Qc > Ksp.

Question 5

A 50.00-mL solution of 0.0426 M trimethylamine (Kb = 6.5 × 10-5)is titrated with a 0.0257 M solution of hydrochloric acid as the titrant.What is the pH of the base solution after 22.31 mL of titrant have been added? (Kw = 1.00 × 10-14)

Accepted Answer

A)  11.21 
B)  10.23 
C)  3.77 
D)  4.19 
E)  12.63

Question 6

What is the pH at the equivalence point when a 25.0 mL sample of 0.200 M aqueous formic acid (HCO2H)is titrated with 0.100 M aqueous potassium hydroxide? (Ka of HCO2H = 1.8 × 10-4)

Accepted Answer

A)  5.71 
B)  7.00 
C)  8.28 
D)  8.52 
E)  10.26

Question 7

Two important biological buffer systems control pH in the range of 6.9 to 7.4.These buffer systems are H₂CO₃/HCO₃^- and _____.

Accepted Answer

The answer of Two important biological buffer systems control pH...

Question 8

What is the maximum hydroxide-ion concentration that a 0.019 M MgCl2 solution could have without causing the precipitation of Mg(OH)2? For Mg(OH)2,Ksp = 1.8 × 10-11.

Accepted Answer

A)  4.2 × 10-6 
B)  1.7 × 10-4 
C)  1.2 × 10-8 
D)  9.5 × 10-9 
E)  3.1 × 10-5

Question 9

What will be the pH of the solution when 0.10 mol of H+ ion is added to a 2.0 liter buffered solution composed of 0.45 M ammonia,NH3,and 0.26 M ammonium fluoride,NH4F? (Kb for ammonia = 1.8 × 10-5)

Accepted Answer

A)  8.07 
B)  4.63 
C)  9.37 
D)  10.34 
E)  4.85

Question 10

The hydroxide ion concentration of a saturated solution of Fe(OH)2 is  M.What is the solubility product constant for Fe(OH)2?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 11

What is the pH of a buffer that results when 0.50 mole of H3PO4 is mixed with 0.75 mole of NaOH and diluted with water to 1.00 L? (The acid dissociation constants of phosphoric acid are Ka1 = 7.5 × 10-3,Ka2 = 6.2 × 10-8,and Ka3 = 3.6 × 10-13)

Accepted Answer

A)  1.82 
B)  2.12 
C)  6.91 
D)  7.21 
E)  12.44

Question 12

How many moles of solid NaF would have to be added to 1.0 L of 2.16 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change.(Ka for HF = 7.2 × 10-4)

Accepted Answer

A)  3.5 
B)  0.45 
C)  0.75 
D)  1.0 
E)  1.6

Question 13

If 25 mL of 0.750 M HCl are added to 100.mL of 0.302 M NaOH,what is the final pH?

Accepted Answer

A)  12.96 
B)  1.04 
C)  13.38 
D)  0.62 
E)  7.00

Question 14

If 20 mL of 0.10 M NaOH is added to 40 mL of 0.20 M HC2H3O2,what is the pH of the resulting solution at 25°C? Ka for HC2H3O2 is 1.8 × 10-5 at 25°C.

Accepted Answer

A)  9.8 
B)  4.1 
C)  5.2 
D)  2.7 
E)  4.3

Question 15

What is the minimum mass of Na2CO3 (molar mass = 105.990 g/mol)that must be added to 43.4 mL of a 1.0 × 10-4 M AgNO3 solution in order for precipitation to occur? The Ksp of Ag2CO3 is 8.6 × 10-12.Assume no volume change occurs upon addition of Na2CO3.

Accepted Answer

A)  4.6 × 10-4 g 
B)  3.1 × 10-4 g 
C)  2.3 × 10-4 g 
D)  4.0 × 10-7 g 
E)  4.0 × 10-3 g

Question 16

When a weak base is titrated with a strong acid,the pH at the equivalence point is _____.

Accepted Answer

A)  less than 7 
B)  greater than 7 
C)  equal to 7 
D)  equal to the acid pKa 
E)  equal to the base pKb

Question 17

All of the following statements concerning acid-base buffers are true EXCEPT

Accepted Answer

A)  buffers are resistant to pH changes upon addition of small quantities of strong acids or bases. 
B)  buffers are used as colored indicators in acid-base titrations. 
C)  the pH of a buffer is close to the pKa of the weak acid from which it is made. 
D)  buffers contain appreciable quantities of a weak acid and its conjugate base. 
E)  buffers are resistant to changes in pH when diluted with water.

Question 18

If 0.50 L of a buffer containing 1.0 mol H2PO4− and 1.0 mol HPO42− is diluted to a volume of 5.0 L,the pH

Accepted Answer

A)  increases by 1. 
B)  decreases by 1. 
C)  increases by 10. 
D)  decreases by 10. 
E)  remains unchanged.

Question 19

If 500 mL of 1.4 × 10-6 M AgNO3 is mixed with 500 mL of 1.4 × 10-6 M NaBr,what will occur? For AgBr,Ksp = 5 × 10-13.

Accepted Answer

A)  Silver(I)bromide will precipitate. 
B)  The concentration of Ag+ will be 1.4 × 10-6 M. 
C)  7.0 × 10-7 mol of AgBr will form. 
D)  No precipitation will occur. 
E)  Sodium bromide will precipitate.

Question 20

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid,HC3H5O2,with strong base?

Accepted Answer

A)  alizarin yellow (transition pH range: 10.0-12.0) 
B)  methyl red (transition pH range: 4.2-6.3) 
C)  methyl orange (transition pH range: 3.1-4.4) 
D)  thymol blue (transition pH range: 8.0-9.6) 
E)  bromothymol blue (transition pH range: 6.2-7.6)

Exam 17: Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

What is the pH of the buffer that results when 32 g sodium acetate (NaCH₃CO₂) is mixed with 500.0 mL of 1.0 M acetic acid (CH₃CO₂H) and diluted with water to 1.0 L? (K_a of CH₃CO₂H = 1.8 × 10^-5)

What molar ratio of acetic acid to sodium acetate is required to create a buffer solution having a pH of 4.88 at 25°C? K_a for HC₂H₃O₂ is 1.8 × 10^-5.

What mass of sodium hydroxide must be added to 65.0 mL of 0.926 M acetic acid in order to create a buffer with a pH of 4.83? K_a for acetic acid is 1.8 × 10^-5.

Suppose 50.00 mL of 2.0 × 10^-5 M Fe(NO₃) ₃ is added to 50.00 mL of 2.0 ×10^-4 M KIO₃.Which of the following statements is true? For Fe(IO₃) ₃,K_sp = 1.0 × 10^-14.

A 50.00-mL solution of 0.0426 M trimethylamine (K_b = 6.5 × 10^-5) is titrated with a 0.0257 M solution of hydrochloric acid as the titrant.What is the pH of the base solution after 22.31 mL of titrant have been added? (K_w = 1.00 × 10^-14)

What is the pH at the equivalence point when a 25.0 mL sample of 0.200 M aqueous formic acid (HCO₂H) is titrated with 0.100 M aqueous potassium hydroxide? (K_a of HCO₂H = 1.8 × 10^-4)

Two important biological buffer systems control pH in the range of 6.9 to 7.4.These buffer systems are H₂CO₃/HCO₃^- and _____.

What is the maximum hydroxide-ion concentration that a 0.019 M MgCl₂ solution could have without causing the precipitation of Mg(OH) ₂? For Mg(OH) ₂,K_sp = 1.8 × 10^-11.

What will be the pH of the solution when 0.10 mol of H⁺ ion is added to a 2.0 liter buffered solution composed of 0.45 M ammonia,NH3,and 0.26 M ammonium fluoride,NH₄F? (K_b for ammonia = 1.8 × 10^-5)

The hydroxide ion concentration of a saturated solution of Fe(OH) ₂ is M.What is the solubility product constant for Fe(OH) ₂?

What is the pH of a buffer that results when 0.50 mole of H₃PO₄ is mixed with 0.75 mole of NaOH and diluted with water to 1.00 L? (The acid dissociation constants of phosphoric acid are K_a1 = 7.5 × 10^-3,K_a2 = 6.2 × 10^-8,and K_a3 = 3.6 × 10^-13)

How many moles of solid NaF would have to be added to 1.0 L of 2.16 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change.(K_a for HF = 7.2 × 10^-4)

If 25 mL of 0.750 M HCl are added to 100.mL of 0.302 M NaOH,what is the final pH?

If 20 mL of 0.10 M NaOH is added to 40 mL of 0.20 M HC₂H₃O₂,what is the pH of the resulting solution at 25°C? K_a for HC₂H₃O₂ is 1.8 × 10^-5 at 25°C.

What is the minimum mass of Na₂CO₃ (molar mass = 105.990 g/mol) that must be added to 43.4 mL of a 1.0 × 10^-4 M AgNO₃ solution in order for precipitation to occur? The K_sp of Ag₂CO₃ is 8.6 × 10^-12.Assume no volume change occurs upon addition of Na₂CO₃.

When a weak base is titrated with a strong acid,the pH at the equivalence point is _____.

All of the following statements concerning acid-base buffers are true EXCEPT

If 0.50 L of a buffer containing 1.0 mol H₂PO₄− and 1.0 mol HPO₄²⁻ is diluted to a volume of 5.0 L,the pH

If 500 mL of 1.4 × 10^-6 M AgNO₃ is mixed with 500 mL of 1.4 × 10^-6 M NaBr,what will occur? For AgBr,K_sp = 5 × 10^-13.

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid,HC₃H₅O₂,with strong base?

Exam 17: Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

What is the pH of the buffer that results when 32 g sodium acetate (NaCH3CO2) is mixed with 500.0 mL of 1.0 M acetic acid (CH3CO2H) and diluted with water to 1.0 L? (Ka of CH3CO2H = 1.8 × 10-5)

What molar ratio of acetic acid to sodium acetate is required to create a buffer solution having a pH of 4.88 at 25°C? Ka for HC2H3O2 is 1.8 × 10-5.

What mass of sodium hydroxide must be added to 65.0 mL of 0.926 M acetic acid in order to create a buffer with a pH of 4.83? Ka for acetic acid is 1.8 × 10-5.

Suppose 50.00 mL of 2.0 × 10-5 M Fe(NO3) 3 is added to 50.00 mL of 2.0 ×10-4 M KIO3.Which of the following statements is true? For Fe(IO3) 3,Ksp = 1.0 × 10-14.

A 50.00-mL solution of 0.0426 M trimethylamine (Kb = 6.5 × 10-5) is titrated with a 0.0257 M solution of hydrochloric acid as the titrant.What is the pH of the base solution after 22.31 mL of titrant have been added? (Kw = 1.00 × 10-14)

What is the pH at the equivalence point when a 25.0 mL sample of 0.200 M aqueous formic acid (HCO2H) is titrated with 0.100 M aqueous potassium hydroxide? (Ka of HCO2H = 1.8 × 10-4)

Two important biological buffer systems control pH in the range of 6.9 to 7.4.These buffer systems are H2CO3/HCO3- and _____.

What is the maximum hydroxide-ion concentration that a 0.019 M MgCl2 solution could have without causing the precipitation of Mg(OH) 2? For Mg(OH) 2,Ksp = 1.8 × 10-11.

What will be the pH of the solution when 0.10 mol of H+ ion is added to a 2.0 liter buffered solution composed of 0.45 M ammonia,NH3,and 0.26 M ammonium fluoride,NH4F? (Kb for ammonia = 1.8 × 10-5)

The hydroxide ion concentration of a saturated solution of Fe(OH) 2 is M.What is the solubility product constant for Fe(OH) 2?

What is the pH of a buffer that results when 0.50 mole of H3PO4 is mixed with 0.75 mole of NaOH and diluted with water to 1.00 L? (The acid dissociation constants of phosphoric acid are Ka1 = 7.5 × 10-3,Ka2 = 6.2 × 10-8,and Ka3 = 3.6 × 10-13)

How many moles of solid NaF would have to be added to 1.0 L of 2.16 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change.(Ka for HF = 7.2 × 10-4)

If 25 mL of 0.750 M HCl are added to 100.mL of 0.302 M NaOH,what is the final pH?

If 20 mL of 0.10 M NaOH is added to 40 mL of 0.20 M HC2H3O2,what is the pH of the resulting solution at 25°C? Ka for HC2H3O2 is 1.8 × 10-5 at 25°C.

What is the minimum mass of Na2CO3 (molar mass = 105.990 g/mol) that must be added to 43.4 mL of a 1.0 × 10-4 M AgNO3 solution in order for precipitation to occur? The Ksp of Ag2CO3 is 8.6 × 10-12.Assume no volume change occurs upon addition of Na2CO3.

When a weak base is titrated with a strong acid,the pH at the equivalence point is _____.

All of the following statements concerning acid-base buffers are true EXCEPT

If 0.50 L of a buffer containing 1.0 mol H2PO4− and 1.0 mol HPO42− is diluted to a volume of 5.0 L,the pH

If 500 mL of 1.4 × 10-6 M AgNO3 is mixed with 500 mL of 1.4 × 10-6 M NaBr,what will occur? For AgBr,Ksp = 5 × 10-13.

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid,HC3H5O2,with strong base?

What is the pH of the buffer that results when 32 g sodium acetate (NaCH₃CO₂) is mixed with 500.0 mL of 1.0 M acetic acid (CH₃CO₂H) and diluted with water to 1.0 L? (K_a of CH₃CO₂H = 1.8 × 10^-5)

What molar ratio of acetic acid to sodium acetate is required to create a buffer solution having a pH of 4.88 at 25°C? K_a for HC₂H₃O₂ is 1.8 × 10^-5.

What mass of sodium hydroxide must be added to 65.0 mL of 0.926 M acetic acid in order to create a buffer with a pH of 4.83? K_a for acetic acid is 1.8 × 10^-5.

Suppose 50.00 mL of 2.0 × 10^-5 M Fe(NO₃) ₃ is added to 50.00 mL of 2.0 ×10^-4 M KIO₃.Which of the following statements is true? For Fe(IO₃) ₃,K_sp = 1.0 × 10^-14.

A 50.00-mL solution of 0.0426 M trimethylamine (K_b = 6.5 × 10^-5) is titrated with a 0.0257 M solution of hydrochloric acid as the titrant.What is the pH of the base solution after 22.31 mL of titrant have been added? (K_w = 1.00 × 10^-14)

What is the pH at the equivalence point when a 25.0 mL sample of 0.200 M aqueous formic acid (HCO₂H) is titrated with 0.100 M aqueous potassium hydroxide? (K_a of HCO₂H = 1.8 × 10^-4)

Two important biological buffer systems control pH in the range of 6.9 to 7.4.These buffer systems are H₂CO₃/HCO₃^- and _____.

What is the maximum hydroxide-ion concentration that a 0.019 M MgCl₂ solution could have without causing the precipitation of Mg(OH) ₂? For Mg(OH) ₂,K_sp = 1.8 × 10^-11.

What will be the pH of the solution when 0.10 mol of H⁺ ion is added to a 2.0 liter buffered solution composed of 0.45 M ammonia,NH3,and 0.26 M ammonium fluoride,NH₄F? (K_b for ammonia = 1.8 × 10^-5)

The hydroxide ion concentration of a saturated solution of Fe(OH) ₂ is M.What is the solubility product constant for Fe(OH) ₂?

What is the pH of a buffer that results when 0.50 mole of H₃PO₄ is mixed with 0.75 mole of NaOH and diluted with water to 1.00 L? (The acid dissociation constants of phosphoric acid are K_a1 = 7.5 × 10^-3,K_a2 = 6.2 × 10^-8,and K_a3 = 3.6 × 10^-13)

How many moles of solid NaF would have to be added to 1.0 L of 2.16 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change.(K_a for HF = 7.2 × 10^-4)

If 20 mL of 0.10 M NaOH is added to 40 mL of 0.20 M HC₂H₃O₂,what is the pH of the resulting solution at 25°C? K_a for HC₂H₃O₂ is 1.8 × 10^-5 at 25°C.

What is the minimum mass of Na₂CO₃ (molar mass = 105.990 g/mol) that must be added to 43.4 mL of a 1.0 × 10^-4 M AgNO₃ solution in order for precipitation to occur? The K_sp of Ag₂CO₃ is 8.6 × 10^-12.Assume no volume change occurs upon addition of Na₂CO₃.

If 0.50 L of a buffer containing 1.0 mol H₂PO₄− and 1.0 mol HPO₄²⁻ is diluted to a volume of 5.0 L,the pH

If 500 mL of 1.4 × 10^-6 M AgNO₃ is mixed with 500 mL of 1.4 × 10^-6 M NaBr,what will occur? For AgBr,K_sp = 5 × 10^-13.

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid,HC₃H₅O₂,with strong base?