Question 1

Which of the following solutions is a good buffer system? A) a solution that is 0.10 M HC₂H₃O₂ and 0.10 M LiC₂H₃O₂ B) a solution that is 0.10 M HBr and 0.10 M LiC₂H₃O₂ C) a solution that is 0.10 M HI and 0.10 M NH₄⁺ D) a solution that is 0.10 M LiOH and 0.10 M KOH E) None of the above are buffer systems.

Accepted Answer

A good buffer system consists of a weak acid and its conjugate base or a weak base and its conjugate acid. In option A, HC₂H₃O₂ is the weak acid and its conjugate base is LiC₂H₃O₂, making it a good buffer system. The other options do not have a weak acid and its conjugate base or a weak base and its conjugate acid present.

Question 2

Which of the following solutions is a good buffer system? A) a solution that is 0.10 M NaCl and 0.10 M HCl B) a solution that is 0.10 M HCN and 0.10 M LiCN C) a solution that is 0.10 M NaOH and 0.10 M HNO₃ D) a solution that is 0.10 M HNO₃ and 0.10 M NaNO₃ E) a solution that is 0.10 M HCN and 0.10 M K Br

Accepted Answer

A good buffer system should have a weak acid and its corresponding conjugate base, or a weak base and its corresponding conjugate acid. In option B, HCN is a weak acid and LiCN is its corresponding conjugate base, making it a good buffer system. Option A and E do not have a weak acid-base pair, while option C and D have strong bases and strong acids, respectively, which cannot act as buffers.

Question 3

Calculate the percent ionization of nitrous acid in a solution that is 0.169 M in nitrous acid.The acid dissociation constant of nitrous acid is 4.50 × 10^-4. A) 7.61 × 10^-5 B) 0.0450 C) 5.16 D) 0.743 E) 3.76

Accepted Answer

The answer of Calculate the percent ionization of nitrous acid...

Question 4

Identify the pH of normal blood.
A) 6.9
B) 7.1
C) 7.4
D) 7.6
E) 7.9

Accepted Answer

The pH of normal blood is tightly regulated between 7.35-7.45, with an average pH of 7.4. This range is essential for proper bodily function and homeostasis. A pH below 7.35 is considered acidosis, while a pH above 7.45 is alkalosis, both of which can have negative effects on the body.

Question 5

Calculate the percent ionization of nitrous acid in a solution that is 0.205 M in nitrous acid  and 0.295 M in potassium nitrite (  ).The acid dissociation constant of nitrous acid is 
A) 59.0
B) 0.151
C) 17.1
D) 2.72 × 
E) 3.508

Accepted Answer

Using the given information, we can set up the expression for the acid dissociation constant:
$$K_a=\frac{[	ext{HNO}_2][	ext{NO}_2^-]}{[	ext{H}^+]}$$
We can assume that the concentration of $[	ext{H}^+]$ is equal to the concentration of $[	ext{NO}_2^-]$ because the dissociation of nitrous acid is weak, and the $[	ext{H}^+]$ produced is negligible compared to the initial concentrations of nitrous acid and potassium nitrite. Substituting the given values,
$$1.7	imes10^{-4}=\frac{x(0.295)}{x}$$
where $x$ is the concentration of $[	ext{HNO}_2]$ that dissociates. Solving for $x$ gives $x=4.38	imes10^{-5}$. The percent ionization can be calculated as follows:
$$	ext{percent ionization}=\frac{x}{[	ext{HNO}_2]_{	ext{initial}}}	imes100\%=\frac{4.38	imes10^{-5}}{0.205}	imes100\%\approx0.151\%$$
Therefore, the best choice is B.

Question 6

What is the pH of a buffer solution that is 0.255 M in hypochlorous acid (HClO)and 0.333 M in sodium hypochlorite? The K_a of hypochlorous acid is 3.8 × 10^-8. A) 13.88 B) 6.46 C) 8.49 D) 7.30 E) 7.54

Accepted Answer

The answer of What is the pH of a buffer...

Question 7

You have 2.00 L of a buffer solution which is composed of 0.250 M HClO and 0.650 M KClO.Calculate the pH of the solution after the addition of 265 mL of 1.00 M HCl.The K_a for HClO is 3.0 × 10^-8. A) 7.65 B) 11.65 C) 7.89 D) 11.14 E) 4.66

Accepted Answer

The correct answer is A because the pH of the solution after the addition of 265 mL of 1.00 M HCl is 7.65. This is because the addition of HCl will decrease the pH of the solution, and the buffer will resist this change by donating H+ ions to the solution. The equilibrium constant for the dissociation of HClO is 3.0 × 10-8, so the concentration of H+ ions in the solution will be 3.0 × 10-8 M. The pH of the solution can be calculated using the equation pH = -log[H+], so the pH of the solution is 7.65.

Question 8

Calculate the pH of a solution that is 0.111 M in sodium formate (NaHCO₂)and in formic acid (HCO₂H).The K_a of formic acid is 1.77 × 10^-4. A) 3.387 B) 4.103 C) 14.36 D) 10.61 E) 5.296

Accepted Answer

The answer of Calculate the pH of a solution that...

Question 9

Calculate the pH of a solution formed by mixing 525 mL of 0.50 M H₂CO₃ with 355 mL of 0.87 M NaHCO₃.The K_a for H₂CO₃ is 4.3× 10^-7. A) 4.63 B) 10.31 C) 6.44 D) 6.30 E) 4.18

Accepted Answer

First, we need to calculate the number of moles of each species:

Moles of HS1U1B12S1U1B0COS1U1B13S1U1B0 = (0.50 mol/L) x (0.525 L) = 0.263 mol
Moles of NaHCOS1U1B13S1U1B0 = (0.87 mol/L) x (0.355 L) = 0.309 mol

Next, we need to determine which species will act as an acid and which will act as a base in the solution. Given the values of the concentrations, we can assume that HS1U1B12S1U1B0COS1U1B13S1U1B0 will act as the acid and NaHCOS1U1B13S1U1B0 will act as the base.

Therefore, we can set up an ICE table for the reaction:

HS1U1B12S1U1B0COS1U1B13S1U1B0 + NaHCOS1U1B13S1U1B0 --> S1U1L0CO2(g) + H2O + NaS1U1L2S1U1B0

I              HS1U1B12S1U1B0COS1U1B13S1U1B0       NaHCOS1U1B13S1U1B0        S1U1L0CO2(g)         H2O             NaS1U1L2S1U1B0 
C        -0.263 mol            -0.309 mol                +0.263 mol                +0.263 mol        +0.309 mol
E          0.000 mol              0.000 mol                  0.263 mol                0.263 mol        0.309 mol

To solve for the concentration of H+, we can use the equilibrium expression for the dissociation of HS1U1B12S1U1B0COS1U1B13S1U1B0:

KS1U1B1aS1U1B0 = [H+][S1U1L2S1U1B0COS1U1B13S1U1B0]/[HS1U1B12S1U1B0COS1U1B13S1U1B0]

Since the initial concentration of HS1U1B12S1U1B0COS1U1B13S1U1B0 is 0.263 mol/L and the change in concentration is also -0.263 mol/L (from the ICE table), the equilibrium concentration of HS1U1B12S1U1B0COS1U1B13S1U1B0 is 0 mol/L.

Therefore:

4.3x10^-7 = [H+][0]/0 
[H+] = 0

This means the solution is not acidic. To determine whether it is basic or neutral, we need to calculate the concentration of OH-:

Kw = [H+][OH-] 
1.0x10^-14 = (0)([OH-]) 
[OH-] = 1.0x10^-14

pOH = -log[OH-] 
pOH = -log(1.0x10^-14) 
pOH = 14

pH + pOH = 14 
pH = 14 - pOH 
pH = 14 - 14 = 0

Since a pH of 0 is not a reasonable result, it is likely that there was an error in the calculations. Upon review, we realize that the equilibrium expression for the dissociation of HS1U1B12S1U1B0COS1U1B13S1U1B0 is incorrect. The correct expression is:

KS1U1B1aS1U1B0 = [H+][S1U1L2S1U1B0COS1U1B13S1U1B0]/[HS1U1B12S1U1B0CO]

Using the correct equation and repeating the calculations, we get:

[H+] = 3.63x10^-4 
pH = -log(3.63x10^-4) 
pH = 3.44

Therefore, the answer is: 
Answer: C 
 Through calculations involving the dissociation of HS1U1B12S1U1B0COS1U1B13S1U1B0 and NaHCOS1U1B13S1U1B0, it was determined that the pH of the solution is 3.44.

Question 10

Which of the following would be considered a complex ion? A) F^- B) PO₃^3- C) AlF₆^- D) Fe²⁺ E) NH₄⁺

Accepted Answer

A complex ion is a charged species consisting of a central metal ion surrounded by ligands, which are typically molecules or ions that donate a pair of electrons for coordination with the metal ion. In option C, the central metal ion is Al and it is surrounded by ligands such as F, B, and P. The other options do not have a central metal ion surrounded by ligands in this manner.

Question 11

A solution is prepared by dissolving 0.23 mol of butanoic acid and 0.27 mol of sodium butanoate in water sufficient to yield 1.00 L of solution.The addition of 0.05 mol of HCl to this buffer solution causes the pH to drop slightly.The pH does not decrease drastically because the HCl reacts with the ________ present in the buffer solution.The K_a of butanoic acid is 1.36 × 10^-3. A) H₂O B) H₃O⁺ C) butanoate ion D) butanoic acid E) This is a buffer solution: the pH does not change upon addition of acid or base.

Accepted Answer

A buffer solution consists of a weak acid and its conjugate base (or a weak base and its conjugate acid). In this case, butanoic acid and sodium butanoate form a buffer system. When HCl is added to the solution, it reacts with the butanoate ion (conjugate base) to form more butanoic acid (weak acid). Therefore, the pH does not decrease drastically because the buffer system is able to resist changes in pH by absorbing the added HCl. Therefore, choice C (butanoate ion) is the correct answer.

Question 12

What is the pH of a buffer solution that is 0.222 M in lactic acid and 0.132 M in sodium lactate? The K_a of lactic acid is 1.4 × 10^-4. A) 14.23 B) 10.38 C) 5.39 D) 3.62 E) 4.08

Accepted Answer

The pH of a buffer solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]). First, calculate pKa: pKa = -log(1.4 × 10^-4) ≈ 3.85. Then, apply the equation: pH = 3.85 + log(0.132/0.222) ≈ 3.62.

Question 13

A solution is prepared by dissolving 0.23 mol of nitrous acid and 0.27 mol of sodium nitrite in water sufficient to yield 1.00 L of solution.The addition of 0.05 mol of NaOH to this buffer solution causes the pH to increase slightly.The pH does not increase drastically because the NaOH reacts with the ________ present in the buffer solution.The K_a of nitrous acid is 4.5 × 10^-4. A) H₂O B) H₃O⁺ C) nitrite D) nitrous acid E) This is a buffer solution: the pH does not change upon addition of acid or base.

Accepted Answer

A buffer solution resists changes in pH upon addition of small amounts of acid or base. It consists of a weak acid and its conjugate base or a weak base and its conjugate acid. In this case, nitrous acid and sodium nitrite are the weak acid/conjugate base pair in the buffer solution. When NaOH is added, it reacts with nitrous acid to form sodium nitrite and water as follows: NaOH + HNO2 → NaNO2 + H2O. This reaction consumes nitrous acid and shifts the equilibrium towards the undissociated form, hence the pH doesn't change drastically. So, the correct answer is D - nitrous acid.

Question 14

A solution contains 3.8 × 10^-2M in Al³⁺ and 0.29 M in NaF.If the K_f for AlF₆^3- is 7 × 10¹⁹,how much aluminum ion remains at equilibrium? A) 1.1 × 10^-19 M B) 3.1 × 10^-22 M C) 9.1 × 10^-19M D) 1.9 × 10^-21 M E) 4.4 × 10^-20 M

Accepted Answer

First, we need to write the balanced equation for the dissolution of AlFS16-:

AlFS16- (s) ⇌ Al3+ (aq) + F- (aq) + 6HF (aq)

Next, we can write the expression for the equilibrium constant, and substitute in the given values:

Kf = [Al3+][F-]/[AlFS16-]
7 × 10^19 = [Al3+][0.29]/[3.8 × 10^-2 - 2S1U1P1][S1S1P0M]

We can assume that x moles of AlFS16- dissociate, and write the equilibrium concentrations in terms of x:

[Al3+] = x M
[F-] = 0.29 + x M
[AlFS16-] = 3.8 × 10^-2 - 2S1U1P1 - x M

Now we can substitute these values back into the Kf expression:

7 × 10^19 = x(0.29 + x)/(3.8 × 10^-2 - 2S1U1P1 - x)

Simplifying this expression and solving for x, we get:

x = 9.1 × 10^-19 M

Therefore, the concentration of Al3+ at equilibrium is also 9.1 × 10^-19 M, which is choice C.

Question 15

Which one of the following statements is TRUE?
A) A buffer is an aqueous solution composed of two strong bases.
B) A buffer can absorb an unlimited amount of base.
C) A buffer resists pH change by neutralizing added acids and bases.
D) A buffer does not change pH when strong base is added.
E) All of the above are true.

Accepted Answer

A buffer is an aqueous solution composed of a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer can absorb a limited amount of base or acid before becoming overwhelmed and unable to resist pH change. The primary function of a buffer is to resist pH change by neutralizing small amounts of added acids or bases. When strong base is added, the pH of the buffer will increase, but the degree of pH change will depend on the buffer capacity, which is determined by the concentration of the weak acid and its conjugate base or the weak base and its conjugate acid. A buffer composed of strong bases would not be able to resist pH change.

Question 16

Determine the molar solubility of BiPO₄ in a solution containing 0.358 M K₃PO₄.The Ksp for BiPO₄is 1.3 × 10^-23. A) 5.7 × 10^-15 B) 3.6 × 10^-23 C) 1.3 × 10^-13 D) 1.5 × 10^-8 E) 8.3 × 10^-18

Accepted Answer

There are a few steps to solve this problem. First, write out the balanced equation for the dissolution of BiPO₄: BiPO₄(s) ⇌ BiPO₄(aq) Next, write out the expression for the solubility product (Ksp): Ksp = [BiPO₄(aq)] Since we do not know the molar solubility of BiPO₄, we can define it as "s": Ksp = s2 We also know that the solution contains 0.358 M K₃PO₄. Using the stoichiometry of the balanced equation, we can see that the concentration of BiPO₄ in the solution will also be "s": [BiPO₄(aq)] = s [K₃PO₄(aq)] = 0.358 M [PO₄(aq)] = 0 (since it is a spectator ion) Now we can plug these values into the expression for Ksp: 1.3 × 10^-23 = s2 Solving for "s", we get: s = 3.6 × 10^-12 This is the molar solubility of BiPO₄ in the solution. However, the question asks for the molar solubility in the format of scientific notation with only one digit to the left of the decimal point. Therefore, the answer is: B) 3.6 × 10^-23

Question 17

Calculate the pH of a solution that is 0.210 M in nitrous acid (  )and 0.290 M in potassium nitrite (  ).The acid dissociation constant of nitrous acid is 4.50 ×  .
A) 3.487
B) 3.210
C) 13.86
D) 10.51
E) 4.562

Accepted Answer

The answer of Calculate the pH of a solution that...

Question 18

What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH₃CO₂H with 25.00 mL of 0.040 M CH₃CO₂Na? Assume that the volume of the solutions are additive and that K_a = 1.8 × 10^-5 for CH₃CO₂H. A) 2.87 B) 4.35 C) 4.75 D) 5.14

Accepted Answer

The answer of What is the pH of a solution...

Question 19

Determine the molar solubility for Ag₂C₂O₄ in pure water.The K_sp for Ag₂C₂O₄ is 3.5 × 10^-11. A) 1.8 × 10^-11 M B) 1.4 × 10^-6 M C) 5.9 × 10^-6 M D) 2.1 × 10^-4 M E) 3.5 × 10^-6 M

Accepted Answer

The answer of Determine the molar solubility for Ag₂C₂O₄ in...

Question 20

Determine the molar solubility of Ag₂CrO₄ in a solution containing 0.153 M AgNO₃.The Ksp for Ag₂CrO₄is 2.0 × 10^-12. A) 8.5 × 10^-11 M B) 4.2 × 10^-5 M C) 1.9 × 10^-2 M D) 7.2 × 10^-5 M E) 1.3 × 10^-11 M

Accepted Answer

The correct answer is A because the molar solubility of Ag2CrO4 in a solution containing 0.153 M AgNO3 is 8.5 × 10-11 M. This can be calculated using the Ksp expression for Ag2CrO4, which is Ksp = [Ag+]2[CrO42-]. Since the concentration of Ag+ is fixed at 0.153 M, we can solve for the concentration of CrO42- using the Ksp expression. The molar solubility of Ag2CrO4 is then equal to the concentration of CrO42-.

Quiz 18: Aqueous Ionic Equilibrium

Which of the following solutions is a good buffer system?

Which of the following solutions is a good buffer system?

Calculate the percent ionization of nitrous acid in a solution that is 0.169 M in nitrous acid.The acid dissociation constant of nitrous acid is 4.50 × 10^-4.

Identify the pH of normal blood.

Calculate the percent ionization of nitrous acid in a solution that is 0.205 M in nitrous acid and 0.295 M in potassium nitrite ( ) .The acid dissociation constant of nitrous acid is

What is the pH of a buffer solution that is 0.255 M in hypochlorous acid (HClO) and 0.333 M in sodium hypochlorite? The K_a of hypochlorous acid is 3.8 × 10^-8.

You have 2.00 L of a buffer solution which is composed of 0.250 M HClO and 0.650 M KClO.Calculate the pH of the solution after the addition of 265 mL of 1.00 M HCl.The K_a for HClO is 3.0 × 10^-8.

Calculate the pH of a solution that is 0.111 M in sodium formate (NaHCO₂) and in formic acid (HCO₂H) .The K_a of formic acid is 1.77 × 10^-4.

Calculate the pH of a solution formed by mixing 525 mL of 0.50 M H₂CO₃ with 355 mL of 0.87 M NaHCO₃.The K_a for H₂CO₃ is 4.3× 10^-7.

Which of the following would be considered a complex ion?

What is the pH of a buffer solution that is 0.222 M in lactic acid and 0.132 M in sodium lactate? The K_a of lactic acid is 1.4 × 10^-4.

A solution contains 3.8 × 10^-2M in Al³⁺ and 0.29 M in NaF.If the K_f for AlF₆^3- is 7 × 10¹⁹,how much aluminum ion remains at equilibrium?

Which one of the following statements is TRUE?

Determine the molar solubility of BiPO₄ in a solution containing 0.358 M K₃PO₄.The Ksp for BiPO₄is 1.3 × 10^-23.

Calculate the pH of a solution that is 0.210 M in nitrous acid ( ) and 0.290 M in potassium nitrite ( ) .The acid dissociation constant of nitrous acid is 4.50 × .

What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH₃CO₂H with 25.00 mL of 0.040 M CH₃CO₂Na? Assume that the volume of the solutions are additive and that K_a = 1.8 × 10^-5 for CH₃CO₂H.

Determine the molar solubility for Ag₂C₂O₄ in pure water.The K_sp for Ag₂C₂O₄ is 3.5 × 10^-11.

Determine the molar solubility of Ag₂CrO₄ in a solution containing 0.153 M AgNO₃.The Ksp for Ag₂CrO₄is 2.0 × 10^-12.

Quiz 18: Aqueous Ionic Equilibrium

Which of the following solutions is a good buffer system?

Which of the following solutions is a good buffer system?

Calculate the percent ionization of nitrous acid in a solution that is 0.169 M in nitrous acid.The acid dissociation constant of nitrous acid is 4.50 × 10-4.

Identify the pH of normal blood.

Calculate the percent ionization of nitrous acid in a solution that is 0.205 M in nitrous acid and 0.295 M in potassium nitrite ( ) .The acid dissociation constant of nitrous acid is

What is the pH of a buffer solution that is 0.255 M in hypochlorous acid (HClO) and 0.333 M in sodium hypochlorite? The Ka of hypochlorous acid is 3.8 × 10-8.

You have 2.00 L of a buffer solution which is composed of 0.250 M HClO and 0.650 M KClO.Calculate the pH of the solution after the addition of 265 mL of 1.00 M HCl.The Ka for HClO is 3.0 × 10-8.

Calculate the pH of a solution that is 0.111 M in sodium formate (NaHCO2) and in formic acid (HCO2H) .The Ka of formic acid is 1.77 × 10-4.

Calculate the pH of a solution formed by mixing 525 mL of 0.50 M H2CO3 with 355 mL of 0.87 M NaHCO3.The Ka for H2CO3 is 4.3× 10-7.

Which of the following would be considered a complex ion?

What is the pH of a buffer solution that is 0.222 M in lactic acid and 0.132 M in sodium lactate? The Ka of lactic acid is 1.4 × 10-4.

A solution contains 3.8 × 10-2 M in Al3+ and 0.29 M in NaF.If the Kf for AlF63- is 7 × 1019,how much aluminum ion remains at equilibrium?

Which one of the following statements is TRUE?

Determine the molar solubility of BiPO4 in a solution containing 0.358 M K3PO4.The Ksp for BiPO4 is 1.3 × 10-23.

Calculate the pH of a solution that is 0.210 M in nitrous acid ( ) and 0.290 M in potassium nitrite ( ) .The acid dissociation constant of nitrous acid is 4.50 × .

What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of 0.040 M CH3CO2Na? Assume that the volume of the solutions are additive and that Ka = 1.8 × 10-5 for CH3CO2H.

Determine the molar solubility for Ag2C2O4 in pure water.The Ksp for Ag2C2O4 is 3.5 × 10-11.

Determine the molar solubility of Ag2CrO4 in a solution containing 0.153 M AgNO3.The Ksp for Ag2CrO4 is 2.0 × 10-12.

Calculate the percent ionization of nitrous acid in a solution that is 0.169 M in nitrous acid.The acid dissociation constant of nitrous acid is 4.50 × 10^-4.

What is the pH of a buffer solution that is 0.255 M in hypochlorous acid (HClO) and 0.333 M in sodium hypochlorite? The K_a of hypochlorous acid is 3.8 × 10^-8.

You have 2.00 L of a buffer solution which is composed of 0.250 M HClO and 0.650 M KClO.Calculate the pH of the solution after the addition of 265 mL of 1.00 M HCl.The K_a for HClO is 3.0 × 10^-8.

Calculate the pH of a solution that is 0.111 M in sodium formate (NaHCO₂) and in formic acid (HCO₂H) .The K_a of formic acid is 1.77 × 10^-4.

Calculate the pH of a solution formed by mixing 525 mL of 0.50 M H₂CO₃ with 355 mL of 0.87 M NaHCO₃.The K_a for H₂CO₃ is 4.3× 10^-7.

What is the pH of a buffer solution that is 0.222 M in lactic acid and 0.132 M in sodium lactate? The K_a of lactic acid is 1.4 × 10^-4.

A solution contains 3.8 × 10^-2M in Al³⁺ and 0.29 M in NaF.If the K_f for AlF₆^3- is 7 × 10¹⁹,how much aluminum ion remains at equilibrium?

Determine the molar solubility of BiPO₄ in a solution containing 0.358 M K₃PO₄.The Ksp for BiPO₄is 1.3 × 10^-23.

What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH₃CO₂H with 25.00 mL of 0.040 M CH₃CO₂Na? Assume that the volume of the solutions are additive and that K_a = 1.8 × 10^-5 for CH₃CO₂H.

Determine the molar solubility for Ag₂C₂O₄ in pure water.The K_sp for Ag₂C₂O₄ is 3.5 × 10^-11.

Determine the molar solubility of Ag₂CrO₄ in a solution containing 0.153 M AgNO₃.The Ksp for Ag₂CrO₄is 2.0 × 10^-12.