Question 1

The solubility of salt MX (solubility product constant K_sp) in water will always be greater than that of salt MX₃ (solubility product constant K'_sp) provided that K_sp > K'_sp.

Accepted Answer

The solubility of a salt depends on its solubility product constant (Ksp) and the stoichiometry of its dissolution. Even if Ksp of MX is greater than that of MX3, the stoichiometry of MX3 (which involves more ions) can result in a different solubility behavior.

Question 2

The equivalence point in a titration is defined as the point when the indicator changes color.

Accepted Answer

The equivalence point in a titration is actually defined as the point when the reaction is complete and the moles of acid equal the moles of base (or vice versa), regardless of whether an indicator changes color or not. Indicators are simply used in titrations to help visualize the endpoint or the point where the indicator changes color, which is close to but not necessarily the same as the equivalence point.

Question 3

Lead(II) iodide, PbI₂, is an ionic compound with a solubility product constant K_sp of 7.9 × 10^-9.Calculate the solubility of this compound in a. pure water. b. 0.50 mol L^-1 KI solution.

Accepted Answer

The answer of Lead(II) iodide, PbI₂, is an ionic compound...

Question 4

Use a carefully drawn and labeled diagram of the titration curve to illustrate the titration of a weak diprotic acid, in which K_a1 and K_a2 are substantially different, with a strong base (base is the titrant). Label as many features of the diagram as possible.

Accepted Answer

The answer of Use a carefully drawn and labeled diagram...

Question 5

Propanoic acid (CH₃CH₂COOH) has a K_a of 1.34 × 10^-5. A 25.00 mL sample of 0.1000 mol L^-1 propanoic acid (in flask) is titrated with 0.1000 mol L^-1 NaOH solution, added from a buret. Carry out the calculations of the quantities indicated below. a. The pH after 0.00 mL of NaOH are added. b. The pH after 15.00 mL of NaOH are added. c. The hydroxide ion concentration after 26.00 mL of NaOH are added.

Accepted Answer

The answer of Propanoic acid (CH₃CH₂COOH) has a K_a of...

Question 6

If the pH of a buffer solution is greater than the pK_a value of the buffer acid, the buffer will have more capacity to neutralize added base than added acid.

Accepted Answer

The answer of If the pH of a buffer solution...

Question 7

Increasing the concentrations of the components of a buffer solution will increase the buffer range.

Accepted Answer

Increasing the concentrations of the components of a buffer solution does not increase the buffer range. The buffer range is determined by the pKa of the weak acid and is independent of the concentrations of the acid and its conjugate base.

Question 8

What is the pH of 375 mL of solution containing 0.150 mol of propenoic acid (HA) and 0.250 mol of sodium propenoate (NaA)? (K_a for propenoic acid is 5.52 × 10^-5.)

Accepted Answer

The answer of What is the pH of 375 mL...

Question 9

Increasing the concentrations of the components of a buffer solution will increase the buffer capacity.

Accepted Answer

This is because the buffer capacity is directly proportional to the concentrations of both the acidic and basic components of the buffer solution. When the concentrations of these components increase, the buffer capacity increases as well, allowing the buffer to effectively resist changes in pH.

Question 10

Hydrochloric acid (0.100 mol L^-1, 25.00 mL aliquot) is being titrated with sodium hydroxide of the same molarity. Calculate the solution pH after addition of 24.80 mL of the sodium hydroxide. Make any reasonable approximations.

Accepted Answer

The answer of Hydrochloric acid (0.100 mol L^-1, 25.00 mL...

Question 11

Calculate the solubility of copper(II) carbonate, CuCO₃, in 1.00 mol L^-1 NH₃. K_sp = 3.0 × 10^-12 for CuCO₃, K_f = 5.6 × 10¹¹ for Cu(NH₃)₄²⁺

Accepted Answer

The answer of Calculate the solubility of copper(II) carbonate, CuCO₃,...

Question 12

Fe(NO₃)₃ (0.00100 mol) and KSCN (0.200 mol) are added to water to make exactly 1 liter of solution. The red complex ion FeSCN²⁺ is produced. Calculate the concentrations of Fe³⁺(aq) and FeSCN²⁺(aq) at equilibrium, if K_f of the FeSCN²⁺ is 8.9 × 10².

Accepted Answer

The answer of Fe(NO₃)₃ (0.00100 mol) and KSCN (0.200 mol)...

Question 13

Hydrofluoric acid (HF) has a K_a value of 7.2 × 10^-4. a. 0.250 mol of F^- ions (in the form of NaF) are added to 1.00 L of 0.100 mol L^-1 aqueous HF. Calculate the resulting pH. b. To the solution produced in (a) is added 10.0 mL of 5.00 mol L^-1 NaOH. Calculate the resulting pH.

Accepted Answer

The answer of Hydrofluoric acid (HF) has a K_a value...

Question 14

Formic acid is a monoprotic acid with a K_a value of 1.8 × 10^-4 at 25°C. a. Calculate the pH of a 0.200 mol L^-1 solution of the acid, making any reasonable approximations. b. If 0.0050 mol of NaOH is added to 100. mL of the solution in (a), calculate the pH of the resultant buffer.

Accepted Answer

The answer of Formic acid is a monoprotic acid with...

Question 15

Silver phosphate, Ag₃PO₄, is an ionic compound with a solubility product constant K_sp of 2.6 × 10^-18. Calculate the solubility of this compound in a. pure water. b. 0.20 mol L^-1 Na₃PO₄ solution.

Accepted Answer

The answer of Silver phosphate, Ag₃PO₄, is an ionic compound...

Question 16

For a diprotic acid H₂A, the relationship K_a1 > K_a2 is always true.

Accepted Answer

In a diprotic acid, the first dissociation constant (Ka1) is always greater than the second dissociation constant (Ka2) because it is easier to remove the first proton from the acid than the second.

Question 17

A CH₃COOH/CH₃COO^- buffer can be produced by adding a strong acid to a solution of CH₃COO^- ions.

Accepted Answer

The CH₃COOH molecule is a weak acid and will partially dissociate in water to form CH₃COO^- ions and H+ ions. Adding a strong acid to this solution will shift the equilibrium towards the non-dissociated CH₃COOH molecule, resulting in a buffer solution consisting of both CH₃COOH and CH₃COO^- ions.

Question 18

The end point in a titration is defined as the point when the indicator changes color.

Accepted Answer

The end point of a titration is indeed defined as the point when the indicator changes color.

Question 19

Make a clear distinction between buffer range and buffer capacity.

Accepted Answer

The answer of Make a clear distinction between buffer range...

Quiz 19: Ionic Equilibria in Aqueous Systems

The solubility of salt MX (solubility product constant Ksp) in water will always be greater than that of salt MX3 (solubility product constant K'sp) provided that Ksp > K'sp.

The equivalence point in a titration is defined as the point when the indicator changes color.

Lead(II) iodide, PbI2, is an ionic compound with a solubility product constant Ksp of 7.9 × 10-9.Calculate the solubility of this compound in a. pure water. b. 0.50 mol L-1 KI solution.

Use a carefully drawn and labeled diagram of the titration curve to illustrate the titration of a weak diprotic acid, in which Ka1 and Ka2 are substantially different, with a strong base (base is the titrant). Label as many features of the diagram as possible.

If the pH of a buffer solution is greater than the pKa value of the buffer acid, the buffer will have more capacity to neutralize added base than added acid.

Increasing the concentrations of the components of a buffer solution will increase the buffer range.

What is the pH of 375 mL of solution containing 0.150 mol of propenoic acid (HA) and 0.250 mol of sodium propenoate (NaA)? (Ka for propenoic acid is 5.52 × 10-5.)

Increasing the concentrations of the components of a buffer solution will increase the buffer capacity.

Hydrochloric acid (0.100 mol L-1, 25.00 mL aliquot) is being titrated with sodium hydroxide of the same molarity. Calculate the solution pH after addition of 24.80 mL of the sodium hydroxide. Make any reasonable approximations.

Calculate the solubility of copper(II) carbonate, CuCO3, in 1.00 mol L-1 NH3. Ksp = 3.0 × 10-12 for CuCO3, Kf = 5.6 × 1011 for Cu(NH3)42+

Fe(NO3)3 (0.00100 mol) and KSCN (0.200 mol) are added to water to make exactly 1 liter of solution. The red complex ion FeSCN2+ is produced. Calculate the concentrations of Fe3+(aq) and FeSCN2+(aq) at equilibrium, if Kf of the FeSCN2+ is 8.9 × 102.

Hydrofluoric acid (HF) has a Ka value of 7.2 × 10-4. a. 0.250 mol of F- ions (in the form of NaF) are added to 1.00 L of 0.100 mol L-1 aqueous HF. Calculate the resulting pH. b. To the solution produced in (a) is added 10.0 mL of 5.00 mol L-1 NaOH. Calculate the resulting pH.

Formic acid is a monoprotic acid with a Ka value of 1.8 × 10-4 at 25°C. a. Calculate the pH of a 0.200 mol L-1 solution of the acid, making any reasonable approximations. b. If 0.0050 mol of NaOH is added to 100. mL of the solution in (a), calculate the pH of the resultant buffer.

Silver phosphate, Ag3PO4, is an ionic compound with a solubility product constant Ksp of 2.6 × 10-18. Calculate the solubility of this compound in a. pure water. b. 0.20 mol L-1 Na3PO4 solution.

For a diprotic acid H2A, the relationship Ka1 > Ka2 is always true.

A CH3COOH/CH3COO- buffer can be produced by adding a strong acid to a solution of CH3COO- ions.