Question 1

What is the selenide ion concentration [Se^2-] for a 0.100 M H₂Se solution that has the stepwise dissociation constants of K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

Accepted Answer

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Question 2

Which of the following is a triprotic acid?

Accepted Answer

A triprotic acid is an acid that can donate three protons (H+) per molecule. Only the compound in choice C, H3PO4 (phosphoric acid), is a triprotic acid.

Question 3

Describe the relationship between molecular structure and acid strength.

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Question 4

What does the term amphoteric mean?

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Question 5

Calculate the pH of a 0.60 M H₂SO₃,solution that has the stepwise dissociation constants K_a1 = 1.5 × 10^-2 and K_a2 = 6.3 × 10^-⁸.

Accepted Answer

The correct answer is A because the pH of a 0.60 M H2SO3 solution that has the stepwise dissociation constants Ka1 = 1.5 × 10-2 and Ka2 = 6.3 × 10-8 is 1.02. This can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where pKa is the negative logarithm of the dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid. For the first dissociation step, pKa1 = -log(1.5 × 10-2) = 1.82, and for the second dissociation step, pKa2 = -log(6.3 × 10-8) = 7.20. Since the concentration of H2SO3 is much greater than the concentration of HSO3- and SO32-, we can assume that [HA] >> [A-] and simplify the equation to pH ≈ pKa1 = 1.82.

Question 6

Do both protons ionize instantaneously from a diprotic acid such as H₂CO₃? Explain your answer.

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Question 7

Which of the following is a Lewis base?

Accepted Answer

In a Lewis acid-base reaction, the Lewis base donates a pair of electrons to the Lewis acid. Out of the given options, only B has an atom (S) with an unshared pair of electrons that can be donated as a Lewis base.

Question 8

What is the autoionization of water?

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Question 9

Match between columns
                        Premises: Lewis base
Lewis acid
Arrhenius acid
Arrhenius base
Brønsted-Lowry acid
Brønsted-Lowry base

Accepted Answer

The Answer of proton acceptor and electron pair donor and is...

Question 10

Identify the strongest acid.

Accepted Answer

HFO₄ is the strongest acid because it has the most oxygen atoms, which increases the acid's ability to stabilize the negative charge on the conjugate base, making it a stronger acid.

Question 11

Describe a molecule that can be a Lewis acid.

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Question 12

List the compound in marble that is destroyed by acid rain.

Accepted Answer

The compound in marble that is destroyed by acid rain is calcium carbonate (CaCO3). Choice C is the only option that contains CaCO3.

Question 13

Calculate the pH of a 0.080 M carbonic acid solution,H₂CO₃₍_aq₎,that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

Accepted Answer

Stepwise dissociation reactions of carbonic acid:
H2CO3 ⇌ H+ + HCO3-
Ka1 = 4.3 × 10-7
HCO3- ⇌ H+ + CO32-
Ka2 = 5.6 × 10-11
To find the pH of a 0.080 M carbonic acid solution, we need to calculate the concentration of H+ ions in the solution at equilibrium.
Let's assume that x moles of H+ ions are generated after the first dissociation. Then the concentration of H+ ions is x M, the concentration of HCO3- is (0.080 - x) M, and the concentration of H2CO3 is (0.080 - x) M (since it's a weak acid, we can assume that the amount of H+ ions from autoionization of water is negligible compared to the amount generated from the dissociation of carbonic acid).
Using the ka1 expression: 
ka1 = [H+][HCO3-]/[H2CO3]
4.3 × 10-7 = x(0.080 - x) / (0.080 - x)
x2 = 4.3 × 10-7 × 0.080
x = 1.23 × 10-4 M
This is the concentration of H+ ions generated from the first dissociation.
Using the ka2 expression:
ka2 = [H+][CO32-]/[HCO3-]
5.6 × 10-11 = x(0.080 - x - 1.23 × 10-4) / (0.080 - 1.23 × 10-4)
x2 = 5.6 × 10-11 × (0.080 - 1.23 × 10-4)
x = 6.06 × 10-7 M
This is the concentration of H+ ions generated from the second dissociation.
The total concentration of H+ ions in solution is the sum of the concentrations from both dissociations: 
[H+] = 1.23 × 10-4 + 6.06 × 10-7 
pH = -log[H+] = 3.73
Therefore, the answer is B.

Question 14

List the compound that is formed from the reaction of carbon dioxide with water.

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Question 15

What is the difference between a strong and weak acid?

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Question 16

What is the pH of a 0.40 M H₂Se solution that has the stepwise dissociation constants K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

Accepted Answer

The pH of the solution can be approximated using the first dissociation constant (Ka1) because the second dissociation constant (Ka2) is much smaller and contributes less to the initial concentration of H+. The pH can be calculated using the formula for a weak acid: pH = 1/2(pKa - log[C]), where [C] is the concentration of the acid. Using Ka1 = 1.3 × 10^-4, pKa1 = -log(1.3 × 10^-4) ≈ 3.89. Thus, pH ≈ 1/2(3.89 - log(0.40)) ≈ 2.14.

Question 17

Acid rain consists primarily of

Accepted Answer

Acid rain is primarily composed of nitric and sulfuric acids that are formed when nitrogen oxides and sulfur dioxide react with water in the atmosphere.

Question 18

List the major source of energy in the United States.

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Question 19

Which of the following is a Lewis acid?

Accepted Answer

A Lewis acid is an electron acceptor, and in this case, Al has an empty p-orbital in its valence shell and can accept an electron pair from a Lewis base. In contrast, the other options do not have an available empty orbital to accept electron pairs and are not Lewis acids.

Question 20

Calculate the concentration of bicarbonate ion,HCO₃^-,in a 0.010 M H₂CO₃ solution that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

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Quiz 16: Acids and Bases

What is the selenide ion concentration [Se^2-] for a 0.100 M H₂Se solution that has the stepwise dissociation constants of K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

Which of the following is a triprotic acid?

Describe the relationship between molecular structure and acid strength.

What does the term amphoteric mean?

Calculate the pH of a 0.60 M H₂SO₃,solution that has the stepwise dissociation constants K_a1 = 1.5 × 10^-2 and K_a2 = 6.3 × 10^-⁸.

Do both protons ionize instantaneously from a diprotic acid such as H₂CO₃? Explain your answer.

Which of the following is a Lewis base?

What is the autoionization of water?

Match the following.

Identify the strongest acid.

Describe a molecule that can be a Lewis acid.

List the compound in marble that is destroyed by acid rain.

Calculate the pH of a 0.080 M carbonic acid solution,H₂CO₃₍_aq₎,that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

List the compound that is formed from the reaction of carbon dioxide with water.

What is the difference between a strong and weak acid?

What is the pH of a 0.40 M H₂Se solution that has the stepwise dissociation constants K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

Acid rain consists primarily of

List the major source of energy in the United States.

Which of the following is a Lewis acid?

Calculate the concentration of bicarbonate ion,HCO₃^-,in a 0.010 M H₂CO₃ solution that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

Quiz 16: Acids and Bases

What is the selenide ion concentration [Se2-] for a 0.100 M H2Se solution that has the stepwise dissociation constants of Ka1 = 1.3 × 10-4 and Ka2 = 1.0 × 10-11?

Which of the following is a triprotic acid?

Describe the relationship between molecular structure and acid strength.

What does the term amphoteric mean?

Calculate the pH of a 0.60 M H2SO3,solution that has the stepwise dissociation constants Ka1 = 1.5 × 10-2 and Ka2 = 6.3 × 10-8.

Do both protons ionize instantaneously from a diprotic acid such as H2CO3? Explain your answer.

Which of the following is a Lewis base?

What is the autoionization of water?

Match the following.

Identify the strongest acid.

Describe a molecule that can be a Lewis acid.

List the compound in marble that is destroyed by acid rain.

Calculate the pH of a 0.080 M carbonic acid solution,H2CO3(aq) , that has the stepwise dissociation constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.

List the compound that is formed from the reaction of carbon dioxide with water.

What is the difference between a strong and weak acid?

What is the pH of a 0.40 M H2Se solution that has the stepwise dissociation constants Ka1 = 1.3 × 10-4 and Ka2 = 1.0 × 10-11?

Acid rain consists primarily of

List the major source of energy in the United States.

Which of the following is a Lewis acid?

Calculate the concentration of bicarbonate ion,HCO3-,in a 0.010 M H2CO3 solution that has the stepwise dissociation constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.

What is the selenide ion concentration [Se^2-] for a 0.100 M H₂Se solution that has the stepwise dissociation constants of K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

Calculate the pH of a 0.60 M H₂SO₃,solution that has the stepwise dissociation constants K_a1 = 1.5 × 10^-2 and K_a2 = 6.3 × 10^-⁸.

Do both protons ionize instantaneously from a diprotic acid such as H₂CO₃? Explain your answer.

Calculate the pH of a 0.080 M carbonic acid solution,H₂CO₃₍_aq₎,that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

What is the pH of a 0.40 M H₂Se solution that has the stepwise dissociation constants K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

Calculate the concentration of bicarbonate ion,HCO₃^-,in a 0.010 M H₂CO₃ solution that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.