Question 1

When comparing the strength of two weak acids which factor do we use to determine which is the stronger of the two?
A) the formula weights of the acids
B) the number of protons the acids can lose
C) the size of the acid dissociation constants
D) none of the above

Accepted Answer

The strength of an acid is determined by its acid dissociation constant (Ka). A larger Ka value indicates a stronger acid. Therefore, option C- the size of the acid dissociation constant is the factor used to determine which of the two weak acids is stronger.

Question 2

Hydrocyanic acid, HCN, is a weaker acid than ammonium ion, NH₄⁺. When hydrocyanic acid reacts with ammonia, NH₃, what species are present in the solution in the largest amount? A) hydrocyanic acid, HCN, and ammonia, NH₃ B) hydrocyanic acid, HCN, and ammonium ion, NH₄⁺ C) cyanide ion, CN-, and ammonia, NH₃ D) cyanide ion, CN-, and ammonium ion, NH₄⁺

Accepted Answer

Since HCN is a weaker acid than NH4+, it will not donate its proton to NH3. Therefore, the predominant species in the solution will be the reactants, HCN and NH3.

Question 3

When acetic acid is dissolved in water which of the following is true of the equilibrium which is established as represented below?   
A) It lies very far to the left.
B) It lies slightly to the left.
C) It lies very far to the right.
D) It lies slightly to the right.

Accepted Answer

The answer of When acetic acid is dissolved in water...

Question 4

When comparing two acids which of the following is true? A) the stronger acid has the larger K_a B) the stronger acid has the smaller pK_a C) both a and b D) neither a nor b

Accepted Answer

The strength of an acid is directly related to its dissociation constant (K_a), so a stronger acid has a larger K_a. The pK_a is the negative logarithm of the K_a, so a stronger acid has a smaller pK_a.

Question 5

Consider the following hypothetical acid-base reaction. A(aq) + B(aq)  C(aq) + D(aq)
Weaker acid weaker base stronger acid stronger base
A) The position of the equilibrium favors the forward reaction.
B) The position of the equilibrium favors the reverse reaction.
C) Neither the forward nor the reverse reaction are favored at equilibrium.
D) The position of equilibrium cannot be predicted from the given data.

Accepted Answer

This reaction involves the transfer of a proton (H+) from A to B. The forward reaction is the ionization of A, which is the acid, and the reverse reaction is the combination of A- and B+, which forms the acid-base conjugate pair. Since the forward reaction involves a weaker acid and a weaker base, while the reverse reaction involves a stronger acid and a stronger base, the position of the equilibrium favors the formation of the acid-base conjugate pair, and thus the reverse reaction. Therefore, choice B is the best answer.

Question 6

What are the two acids in the following reaction? NH₄⁺(aq) + HPO₄^2- NH₃ + H₂PO₄^- A) NH₄⁺ and HPO₄2^- B) NH₄⁺ and NH₃ C) HPO₄2^- and H₂PO₄^- D) NH₄⁺ and H₂PO₄^-

Accepted Answer

The two acids in the reaction are NH₄⁺ and H₂PO₄^-, which form the acid-base pair. Option D correctly identifies these two acids.

Question 7

When comparing the strength of two weak acids which factor do we use to determine which is the stronger of the two? A) the formula weights of the acids B) the number of protons the acids can lose C) the values of the pK_a's of the acids D) none of the above

Accepted Answer

The value of the pKa (acid dissociation constant) is a measure of the strength of an acid. The lower the pKa value, the stronger the acid. Therefore, by comparing the pKa values of two weak acids, we can determine which one is stronger.

Question 8

The pK_a of hydrocyanic acid is 9.31. What is the K_a of hydrocyanic acid? A) 1.3 × 10^-24 B) 1.3 × 10^-10 C) 4.9 × 10^-10 D) 2.0 × 10⁹

Accepted Answer

The answer of The pK_a of hydrocyanic acid is 9.31....

Question 9

In an acid-base equilibrium the equilibrium lies in the direction which favors which species?
A) the weaker acid
B) the weaker base
C) both a and b
D) neither a nor b

Accepted Answer

In an acid-base equilibrium, the equilibrium lies in the direction that favors the weaker acid and weaker base. This is because the stronger acid/base will tend to react to form the weaker acid/base and shift the equilibrium to the oppositely favored direction. Therefore, both choices A and B are correct.

Question 10

Cyanide ion, CN-, is a stronger base than ammonia, NH₃. When ammonia reacts with hydrocyanic acid, HCN, what species are present in the solution in the largest amount? A) hydrocyanic acid, HCN, and ammonia, NH₃ B) hydrocyanic acid, HCN, and ammonium ion, NH₄⁺ C) cyanide ion, CN-, and ammonia, NH₃ D) cyanide ion, CN-, and ammonium ion, NH₄⁺

Accepted Answer

The answer of Cyanide ion, CN-, is a stronger base...

Question 11

The K_a for lactic acid is 8.4 × 10^-4. What is the pK_a of lactic acid? A) -10.92 B) -3.08 C) 3.08 D) 10.92

Accepted Answer

The pKa is calculated using the formula pKa = -log(Ka). For lactic acid, pKa = -log(8.4 × 10^-4) = 3.08.

Question 12

In an acid-base equilibrium the equilibrium lies in the direction which favors which species?
A) the stronger acid
B) the weaker base
C) both a and b
D) neither a nor b

Accepted Answer

The answer of In an acid-base equilibrium the equilibrium lies...

Question 13

When HCl is dissolved in water which of the following is true of the equilibrium which is established?
A) It lies virtually completely to the left.
B) It lies slightly to the left.
C) It lies virtually completely to the right.
D) It lies slightly to the right.

Accepted Answer

When HCl is dissolved in water, it dissociates into H+ and Cl- ions. The dissociation of HCl in water is nearly 100%, which means that the equilibrium lies virtually completely to the right.

Question 14

Acetic acid, CH₃COOH, is a stronger acid than the ammonium ion, NH₄⁺. When acetic acid reacts with ammonia, NH₃, what species are present in the solution in the largest amount? A) acetic acid, CH₃COOH and ammonia, NH₃ B) acetic acid, CH₃COOH, and ammonium, NH₄⁺ C) acetate ion, CH₃COO^-, and ammonia, NH₃ D) acetate ion, CH₃COO^-, and ammonium ion, NH₄⁺

Accepted Answer

When acetic acid reacts with ammonia, they will form ammonium ion and acetate ion. However, since acetic acid is a stronger acid than ammonium ion, it will donate a proton to ammonia to form ammonium ion and acetate ion. Therefore, the species present in the largest amount would be acetate ion and ammonium ion, which are the products of the reaction. Hence, the best choice is D.

Question 15

The K_a for boric acid is 7.3 × 10^¯10. What is the pK_a of boric acid? A) -9.14 B) -4.86 C) 4.86 D) 9.14

Accepted Answer

The answer of The K_a for boric acid is 7.3...

Question 16

Ammonia , NH₃, is a stronger base than the acetate ion, CH₃COO^-. When acetic acid, CH₃COOH, reacts with ammonia, NH₃, what species are present in the solution in the largest amount? A) acetic acid, CH₃COOH, and ammonia, NH₃ B) acetic acid, CH₃COOH, and ammonium, NH₄⁺ C) acetate ion, CH₃COO^-, and ammonia, NH₃ D) acetate ion, CH₃COO^-, and ammonium ion, NH₄⁺

Accepted Answer

When acetic acid reacts with ammonia, the acetic acid donates a proton to the ammonia, forming acetate ions and ammonium ions. Since ammonia is a stronger base than the acetate ion, the reaction favors the formation of these products.

Question 17

When comparing two acids which of the following is true? A) the stronger acid has the larger K_a B) the stronger acid has the larger pK_a C) both a and b D) neither a nor b

Accepted Answer

The strength of an acid is directly related to its acid dissociation constant (K_a). A larger K_a indicates a stronger acid. Conversely, a larger pK_a (which is the negative logarithm of K_a) indicates a weaker acid.

Question 18

When comparing the strength of two weak acids which factor(s) do we use to determine which is the stronger of the two? A) the size of the acid dissociation constants B) the values of the pK_a's of the acids C) either a or b D) neither a nor b

Accepted Answer

To compare the strength of two weak acids, either the size of the acid dissociation constants or the values of the pK's of the acids can be used. Therefore, choice C is the best answer.

Question 19

When NH₃ is dissolved in water which of the following is true of the equilibrium which is established as represented below? NH₃(aq) + H₂O(l) NH₄⁺(aq) + OH^-(aq) A) It lies virtually completely to the left. B) It lies slightly to the left. C) It lies virtually completely to the right. D) It lies slightly to the right.

Accepted Answer

The answer of When NH₃ is dissolved in water which...

Question 20

When comparing two acids which of the following is true? A) the stronger acid has the smaller K_a B) the stronger acid has the larger pK_a C) both a and b D) neither a nor b

Accepted Answer

The answer of When comparing two acids which of the...

Quiz 8: Acids and Bases

When comparing the strength of two weak acids which factor do we use to determine which is the stronger of the two?

Hydrocyanic acid, HCN, is a weaker acid than ammonium ion, NH4+. When hydrocyanic acid reacts with ammonia, NH3, what species are present in the solution in the largest amount?

When acetic acid is dissolved in water which of the following is true of the equilibrium which is established as represented below?

When comparing two acids which of the following is true?

Consider the following hypothetical acid-base reaction. A(aq) + B(aq) C(aq) + D(aq) Weaker acid weaker base stronger acid stronger base

What are the two acids in the following reaction? NH4+(aq) + HPO42- NH3 + H2PO4-

When comparing the strength of two weak acids which factor do we use to determine which is the stronger of the two?

The pKa of hydrocyanic acid is 9.31. What is the Ka of hydrocyanic acid?

In an acid-base equilibrium the equilibrium lies in the direction which favors which species?

Cyanide ion, CN-, is a stronger base than ammonia, NH3. When ammonia reacts with hydrocyanic acid, HCN, what species are present in the solution in the largest amount?

The Ka for lactic acid is 8.4 × 10-4. What is the pKa of lactic acid?

In an acid-base equilibrium the equilibrium lies in the direction which favors which species?

When HCl is dissolved in water which of the following is true of the equilibrium which is established?

Acetic acid, CH3COOH, is a stronger acid than the ammonium ion, NH4+. When acetic acid reacts with ammonia, NH3, what species are present in the solution in the largest amount?

The Ka for boric acid is 7.3 × 10¯10. What is the pKa of boric acid?

Ammonia , NH3, is a stronger base than the acetate ion, CH3COO-. When acetic acid, CH3COOH, reacts with ammonia, NH3, what species are present in the solution in the largest amount?

When comparing two acids which of the following is true?

When comparing the strength of two weak acids which factor(s) do we use to determine which is the stronger of the two?

When NH3 is dissolved in water which of the following is true of the equilibrium which is established as represented below? NH3(aq) + H2O(l) NH4+(aq) + OH-(aq)

When comparing two acids which of the following is true?

Hydrocyanic acid, HCN, is a weaker acid than ammonium ion, NH₄⁺. When hydrocyanic acid reacts with ammonia, NH₃, what species are present in the solution in the largest amount?

What are the two acids in the following reaction? NH₄⁺(aq) + HPO₄^2- NH₃ + H₂PO₄^-

The pK_a of hydrocyanic acid is 9.31. What is the K_a of hydrocyanic acid?

Cyanide ion, CN-, is a stronger base than ammonia, NH₃. When ammonia reacts with hydrocyanic acid, HCN, what species are present in the solution in the largest amount?

The K_a for lactic acid is 8.4 × 10^-4. What is the pK_a of lactic acid?

Acetic acid, CH₃COOH, is a stronger acid than the ammonium ion, NH₄⁺. When acetic acid reacts with ammonia, NH₃, what species are present in the solution in the largest amount?

The K_a for boric acid is 7.3 × 10^¯10. What is the pK_a of boric acid?

Ammonia , NH₃, is a stronger base than the acetate ion, CH₃COO^-. When acetic acid, CH₃COOH, reacts with ammonia, NH₃, what species are present in the solution in the largest amount?

When NH₃ is dissolved in water which of the following is true of the equilibrium which is established as represented below? NH₃(aq) + H₂O(l) NH₄⁺(aq) + OH^-(aq)