Question 1

Calculate the mole ratio of CH3COONa to CH3COOH required to make a buffer with pH of 4.83. Ka of CH3COOH is 1.8 × 10-5.

Accepted Answer

A)  0.122 
B)  3.00 
C)  0.75 
D)  1.22 
E)  10.0 
A)  0.122 
B)  3.00 
C)  0.75 
D)  1.22 
E)  10.0

Question 2

How many millilitres of 0.120 mol L-1 NaOH are required to titrate 50.0 mL of 0.0998 mol L-1 acetic acid to the equivalence point? Acetic acid is monoprotic. The   of acetic acid is 1.8 × 10-5.

Accepted Answer

A)  41.6 
B)  60.1 
C)  50.0 
D)  1.77 
E)  2.82 
A)  41.6 
B)  60.1 
C)  50.0 
D)  1.77 
E)  2.82

Question 3

A 100.0 mL sample of 0.10 mol L-1 Ca(OH)2 is titrated with 0.10 mol L-1 HBr. Determine the pH of the solution after the addition of 200.0 mL HBr.

Accepted Answer

A)  2.62 
B)  2.00 
C)  1.48 
D)  12.52 
E)  7.00 
A)  2.62 
B)  2.00 
C)  1.48 
D)  12.52 
E)  7.00

Question 4

Identify the salts that are in hard water.

Accepted Answer

A)  CaCO3 and MgCO3 
B)  MgSO4 and CaSO4 
C)  NaCl and KBr 
D)  NaHSO4 and Na2SO4 
E)  NaOCl and HOCl 
A)  CaCO3 and MgCO3 
B)  MgSO4 and CaSO4 
C)  NaCl and KBr 
D)  NaHSO4 and Na2SO4 
E)  NaOCl and HOCl

Question 5

A buffer solution is 0.100 mol L-1 in both C6H5COOH and C6H5COOLi and has a pH of 4.19. Which of the following pH values would you expect after the addition of a small amount of a strong base?

Accepted Answer

A)  3.89 
B)  3.69 
C)  5.69 
D)  4.49 
E)  8.89 
A)  3.89 
B)  3.69 
C)  5.69 
D)  4.49 
E)  8.89

Question 6

Calculate the pH of a buffer that is 0.105 mol L-1 CH3COOH and 0.146 mol L-1 CH3COOK. The Ka for CH3COOH is 1.8 × 10-5.

Accepted Answer

A)  4.89 
B)  9.11 
C)  4.74 
D)  9.26 
E)  4.60 
A)  4.89 
B)  9.11 
C)  4.74 
D)  9.26 
E)  4.60

Question 7

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONa buffer solution is 3.89, which of the following is TRUE?

Accepted Answer

A) [HCOOH] [HCOONa] D) [HCOOH] >> [HCOONa] E) [HCOOH] << [HCOONa] A) [HCOOH] [HCOONa] D) [HCOOH] >> [HCOONa] E) [HCOOH] << [HCOONa]

Question 8

Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 32.00 mL of 0.500 mol L-1 HCl to reach the equivalence point?

Accepted Answer

A)  0. 300 mol L-1 
B)  0. 312 mol L-1 
C)  0. 800 mol L-1 
D)  1. 30 mol L-1 
A)  0. 300 mol L-1 
B)  0. 312 mol L-1 
C)  0. 800 mol L-1 
D)  1. 30 mol L-1

Question 9

An acid solution is 0.100 mol L-1 in HCl and 0.200 mol L-1     . What volume of a 0.150 mol L-1 KOH solution would completely neutralize 500.0 mL of this solution?

Accepted Answer

A)  0.700 L 
B)  1.98 L 
C)  1.67 L 
D)  1.02 L 
E)  0.250 L 
A)  0.700 L 
B)  1.98 L 
C)  1.67 L 
D)  1.02 L 
E)  0.250 L

Question 10

Determine the molar solubility of CaSO4 in a solution containing 0.100 mol L-1 Na2SO4. Ksp (CaSO4) = 2.4 × 10-5.

Accepted Answer

A)  4.9 × 10-3 mol L-1 
B)  2.4 × 10-4 mol L-1 
C)  5.8 × 10-10 mol L-1 
D)  1.2 × 10-5 mol L-1 
E)  0.10 mol L-1 
A)  4.9 × 10-3 mol L-1 
B)  2.4 × 10-4 mol L-1 
C)  5.8 × 10-10 mol L-1 
D)  1.2 × 10-5 mol L-1 
E)  0.10 mol L-1

Question 11

A 100.0 mL sample of 0.18 mol L-1 HClO4 is titrated with 0.27 mol L-1 NaOH. Determine the pH of the solution before the addition of any NaOH.

Accepted Answer

A)  1.74 
B)  1.05 
C)  0.74 
D)  0.57 
E)  1.57 
A)  1.74 
B)  1.05 
C)  0.74 
D)  0.57 
E)  1.57

Question 12

A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the precipitate after the addition of 6 mol L-1 HCl; H2S and 0.2 mol L-1 HCl; OH- to a pH of 8; and (NH4)2HPO4 with NH3.

Accepted Answer

A)  Ba3(PO4)2 
B)  CdS 
C)  AgCl 
D)  NH4Cl 
E)  ZnS 
A)  Ba3(PO4)2 
B)  CdS 
C)  AgCl 
D)  NH4Cl 
E)  ZnS

Question 13

A 100.0 mL sample of 0.10 mol L-1 Ca(OH)2 is titrated with 0.10 mol L-1 HBr. Determine the pH of the solution after the addition of 400.0 mL HBr.

Accepted Answer

A)  1.00 
B)  1.40 
C)  1.22 
D)  1.30 
E)  2.11 
A)  1.00 
B)  1.40 
C)  1.22 
D)  1.30 
E)  2.11

Question 14

Calculate the pH of a buffer that is 0.020 mol L-1 HF and 0.040 mol L-1 LiF. The Ka for HF is 3.5 × 10-4.

Accepted Answer

A)  2.06 
B)  4.86 
C)  3.16 
D)  3.46 
E)  3.76 
A)  2.06 
B)  4.86 
C)  3.16 
D)  3.46 
E)  3.76

Question 15

What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 mol L-1 HCN with 50.00 mL of   NaCN? Assume that the volumes of the solutions are additive and that Ka =

Accepted Answer

A)  1.5 × 10-10 mol L-1 
B)  4.9 × 10-10 mol L-1 
C)  1.6 × 10-9 mol L-1 
D)  7.0 × 10-6 mol L-1 
A)  1.5 × 10-10 mol L-1 
B)  4.9 × 10-10 mol L-1 
C)  1.6 × 10-9 mol L-1 
D)  7.0 × 10-6 mol L-1

Question 16

Identify the indicator that can be used at the lowest pH.

Accepted Answer

A)  alizarin 
B)  thymol blue 
C)  crystal violet 
D)  phenolphthalein 
E)  alizarin yellow R 
A)  alizarin 
B)  thymol blue 
C)  crystal violet 
D)  phenolphthalein 
E)  alizarin yellow R

Question 17

Give the name of the compound that is in antifreeze and is toxic to pets.

Accepted Answer

Ethylene g

Question 18

A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the soluble salt remaining in the solution after the addition of 6 mol L-1 HCl, followed by the addition of H2S and 0.2 mol L-1 HCl, then the addition of OH- to a pH of 8, and finally the addition of (NH4)2HPO4 with NH3.

Accepted Answer

A)  Ba3(PO4)2 
B)  CdS 
C)  AgCl 
D)  NH4Cl 
E)  ZnS 
A)  Ba3(PO4)2 
B)  CdS 
C)  AgCl 
D)  NH4Cl 
E)  ZnS

Question 19

Which of the following acids (listed with pKa values) and its conjugate would be the best choice to make a buffer with a pH of 8.10?

Accepted Answer

A)  HC7H5O2, pKa = 4.19 
B)  HF, pKa = 3.46 
C)  HClO, pKa = 7.54 
D)  HCN, pKa = 9.31 
E)  HClO2, pKa = 1.96 
A)  HC7H5O2, pKa = 4.19 
B)  HF, pKa = 3.46 
C)  HClO, pKa = 7.54 
D)  HCN, pKa = 9.31 
E)  HClO2, pKa = 1.96

Question 20

A 100.0 mL sample of 0.18 mol L-1 HClO4 is titrated with 0.27 mol L-1 NaOH. Determine the pH of the solution after the addition of 100.0 mL of NaOH.

Accepted Answer

A)  13.1 
B)  12.7 
C)  1.3 
D)  0.9 
E)  12.9 
A)  13.1 
B)  12.7 
C)  1.3 
D)  0.9 
E)  12.9

Exam 16: Aqueous Ionic Equilibrium

Calculate the mole ratio of CH3COONa to CH3COOH required to make a buffer with pH of 4.83. Ka of CH3COOH is 1.8 × 10-5.

How many millilitres of 0.120 mol L-1 NaOH are required to titrate 50.0 mL of 0.0998 mol L-1 acetic acid to the equivalence point? Acetic acid is monoprotic. The of acetic acid is 1.8 × 10-5.

A 100.0 mL sample of 0.10 mol L-1 Ca(OH)2 is titrated with 0.10 mol L-1 HBr. Determine the pH of the solution after the addition of 200.0 mL HBr.

Identify the salts that are in hard water.

A buffer solution is 0.100 mol L-1 in both C6H5COOH and C6H5COOLi and has a pH of 4.19. Which of the following pH values would you expect after the addition of a small amount of a strong base?

Calculate the pH of a buffer that is 0.105 mol L-1 CH3COOH and 0.146 mol L-1 CH3COOK. The Ka for CH3COOH is 1.8 × 10-5.

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONa buffer solution is 3.89, which of the following is TRUE?

Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 32.00 mL of 0.500 mol L-1 HCl to reach the equivalence point?

An acid solution is 0.100 mol L-1 in HCl and 0.200 mol L-1 . What volume of a 0.150 mol L-1 KOH solution would completely neutralize 500.0 mL of this solution?

Determine the molar solubility of CaSO4 in a solution containing 0.100 mol L-1 Na2SO4. Ksp (CaSO4) = 2.4 × 10-5.

A 100.0 mL sample of 0.18 mol L-1 HClO4 is titrated with 0.27 mol L-1 NaOH. Determine the pH of the solution before the addition of any NaOH.

A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the precipitate after the addition of 6 mol L-1 HCl; H2S and 0.2 mol L-1 HCl; OH- to a pH of 8; and (NH4)2HPO4 with NH3.

A 100.0 mL sample of 0.10 mol L-1 Ca(OH)2 is titrated with 0.10 mol L-1 HBr. Determine the pH of the solution after the addition of 400.0 mL HBr.

Calculate the pH of a buffer that is 0.020 mol L-1 HF and 0.040 mol L-1 LiF. The Ka for HF is 3.5 × 10-4.

What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 mol L-1 HCN with 50.00 mL of NaCN? Assume that the volumes of the solutions are additive and that Ka =

Identify the indicator that can be used at the lowest pH.

Give the name of the compound that is in antifreeze and is toxic to pets.

A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the soluble salt remaining in the solution after the addition of 6 mol L-1 HCl, followed by the addition of H2S and 0.2 mol L-1 HCl, then the addition of OH- to a pH of 8, and finally the addition of (NH4)2HPO4 with NH3.

Which of the following acids (listed with pKa values) and its conjugate would be the best choice to make a buffer with a pH of 8.10?

A 100.0 mL sample of 0.18 mol L-1 HClO4 is titrated with 0.27 mol L-1 NaOH. Determine the pH of the solution after the addition of 100.0 mL of NaOH.

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Calculate the mole ratio of CH₃COONa to CH₃COOH required to make a buffer with pH of 4.83. K_a of CH₃COOH is 1.8 × 10^-5.

How many millilitres of 0.120 mol L^-1 NaOH are required to titrate 50.0 mL of 0.0998 mol L^-1 acetic acid to the equivalence point? Acetic acid is monoprotic. The of acetic acid is 1.8 × 10^-5.

A 100.0 mL sample of 0.10 mol L^-1 Ca(OH)₂ is titrated with 0.10 mol L^-1 HBr. Determine the pH of the solution after the addition of 200.0 mL HBr.

A buffer solution is 0.100 mol L^-1 in both C₆H₅COOH and C₆H₅COOLi and has a pH of 4.19. Which of the following pH values would you expect after the addition of a small amount of a strong base?

Calculate the pH of a buffer that is 0.105 mol L^-1 CH₃COOH and 0.146 mol L^-1 CH₃COOK. The K_a for CH₃COOH is 1.8 × 10^-5.

If the pK_aof HCOOH is 3.74 and the pH of an HCOOH/HCOONabuffer solution is 3.89, which of the following is TRUE?

Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 32.00 mL of 0.500 mol L^-1 HCl to reach the equivalence point?

An acid solution is 0.100 mol L^-1 in HCl and 0.200 mol L^-1 . What volume of a 0.150 mol L^-1 KOH solution would completely neutralize 500.0 mL of this solution?

Determine the molar solubility of CaSO₄ in a solution containing 0.100 mol L^-1 Na₂SO₄. K_sp (CaSO₄) = 2.4 × 10^-5.

A 100.0 mL sample of 0.18 mol L^-1 HClO₄ is titrated with 0.27 mol L^-1 NaOH. Determine the pH of the solution before the addition of any NaOH.

A sample contains Ba₃(PO₄)₂,CdS, AgCl, NH₄Cl, and ZnS. Identify the precipitate after the addition of 6 mol L^-1 HCl; H₂S and 0.2 mol L^-1 HCl; OH^-to a pH of 8; and (NH₄)₂HPO₄ with NH₃.

A 100.0 mL sample of 0.10 mol L^-1 Ca(OH)₂ is titrated with 0.10 mol L^-1 HBr. Determine the pH of the solution after the addition of 400.0 mL HBr.

Calculate the pH of a buffer that is 0.020 mol L^-1 HF and 0.040 mol L^-1 LiF. The K_a for HF is 3.5 × 10^-4.

What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 mol L^-1 HCN with 50.00 mL of NaCN? Assume that the volumes of the solutions are additive and that K_a =

Which of the following acids (listed with pK_a values) and its conjugate would be the best choice to make a buffer with a pH of 8.10?

A 100.0 mL sample of 0.18 mol L^-1 HClO₄ is titrated with 0.27 mol L^-1 NaOH. Determine the pH of the solution after the addition of 100.0 mL of NaOH.