Question 1

An aqueous solution of ________ will produce a neutral solution.

Accepted Answer

LiNO3 is a salt formed from a strong acid (HNO3) and a strong base (LiOH), which results in a neutral solution when dissolved in water.

Question 2

Hydrochloric acid is a strong acid. This means that ________.

Accepted Answer

A strong acid completely dissociates into its respective ions when it is dissolved in water. Therefore, option A is the correct answer. Option B is incorrect, as it contradicts the definition of a strong acid. Option C is not necessarily true and is irrelevant to the properties of hydrochloric acid. Option D is incorrect, as a weak base can still neutralize a strong acid. Option E is incorrect, as hydrochloric acid does not contain hydroxide ions in its formula.

Question 3

A 0.1 M aqueous solution of ________ will have a pH of 7.0 at 25.0 °C. LiF RbBr NaClO₄ NH₄Cl

Accepted Answer

RbBr and NaClO₄ are salts of strong acids and strong bases, which do not hydrolyze in water, resulting in a neutral pH of 7.0.

Question 4

Calculate the pH of a 0.500 M aqueous solution of NH₃. The K_b of NH₃ is 1.77 × 10^-⁵.

Accepted Answer

To find the pH, first calculate the pOH using the formula: pOH = -log[OH⁻]. For NH₃, [OH⁻] can be found using the formula: [OH⁻] = √(Kb × [NH₃]). Substituting the given values, [OH⁻] = √(1.77 × 10⁻⁵ × 0.500) = √(8.85 × 10⁻⁶) ≈ 2.97 × 10⁻³. Then, pOH = -log(2.97 × 10⁻³) ≈ 2.53. Finally, pH = 14 - pOH = 14 - 2.53 = 11.47.

Question 5

In which of the following aqueous solutions does the weak acid exhibit the highest percentage ionization?

Accepted Answer

The percentage ionization of a weak acid is higher when the acid dissociation constant (K_a) is larger. H₂SO₃ has the highest K_a value among the given options, indicating the highest percentage ionization.

Question 6

A 1.0 × 10^-2 M aqueous solution of Ca(OH)₂ at 25.0 °C has a pH of ________.

Accepted Answer

Ca(OH)2 is a strong base and completely dissociates in water to form Ca2+ and OH- ions. The concentration of OH- ions is twice the concentration of Ca2+ ions. Using the formula pH = 14 - pOH, we can calculate the pOH of the solution: pOH = -log[OH-] = -log(2.0 × 10^-2) = 1.70. Therefore, the pH of the solution is 14 - 1.70 = 12.30. Choice A is the correct answer.

Question 7

An aqueous solution contains 0.10 M HNO₃. The solution is ________.

Accepted Answer

HNO₃ is a weak acid and will partially dissociate in water to produce H+ ions. The presence of H+ ions in the solution makes it acidic.

Question 8

The K_a of hydrazoic acid (HN₃)is 1.9 × 10^-⁵ at 25.0 °C. What is the pH of a 0.15 M aqueous solution of HN₃?

Accepted Answer

To find the pH, we first set up the expression for the dissociation of HN3: HN3 ⇌ H+ + N3-. Using the Ka value, we set up the equation: Ka = [H+][N3-]/[HN3]. Assuming x is the concentration of H+ ions, we have Ka = x^2/(0.15-x) ≈ x^2/0.15. Solving for x gives x ≈ 1.7 × 10^-3. The pH is -log(1.7 × 10^-3) ≈ 2.77.

Question 9

What is the pOH of a 0.030 M solution of barium hydroxide?

Accepted Answer

Barium hydroxide, Ba(OH)2, dissociates into two hydroxide ions (OH-) per formula unit. Therefore, a 0.030 M solution of Ba(OH)2 results in a 0.060 M concentration of OH-. The pOH is calculated as -log[OH-], which is -log(0.060) = 1.22.

Question 10

What is the concentration (in M)of hydroxide ions in a solution at 25.0 °C with pH = 4.282?

Accepted Answer

Since pH + pOH = 14 at 25.0 °C, we can calculate the pOH:

pOH = 14 - pH = 14 - 4.282 = 9.718

Then, we can calculate the concentration of hydroxide ions using:

[OH-] = 10^(-pOH) = 10^(-9.718) = 1.92 × 10^(-10)

Therefore, the concentration (in M) of hydroxide ions in the solution is 1.92 × 10^(-10) M, which corresponds to choice C.

Question 11

Which solution will be the most basic?

Accepted Answer

The answer of Which solution will be the most basic?
...

Question 12

The K_a of hydrofluoric acid (HF)at 25.0 °C is 6.8 × 10^-4. What is the pH of a 0.45 M aqueous solution of HF?

Accepted Answer

The answer of The K_a of hydrofluoric acid (HF)at 25.0...

Question 13

In which of the following aqueous solutions does the weak acid exhibit the lowest percentage ionization?

Accepted Answer

The lower the K_a value, the weaker the acid and the lower the percentage ionization. HCN has the lowest K_a value, so it exhibits the lowest percentage ionization.

Question 14

The K_a of hypochlorous acid (HClO)is 3.0 × 10^-⁸ at 25.0 °C. Calculate the pH of a 0.0385 M hypochlorous acid solution.

Accepted Answer

The dissociation of hypochlorous acid is represented as:
HClO + H2O ⇌ ClO- + H3O+

The Ka expression for this reaction is:
Ka = [ClO-][H3O+]/[HClO]

Using the given Ka value, we can write:
3.0 × 10^-8 = [ClO-][H3O+]/[HClO]
Since the initial concentration of HClO is 0.0385 M, let x be the concentration of H+ ions and ClO- ions formed at equilibrium.

Thus, we can write:
[H3O+] = x
[ClO-] = x
[HClO] = 0.0385 - x

Substituting these values in the Ka expression and solving for x, we get:
x = 1.9 × 10^-5

Taking the negative logarithm of this concentration gives us the pH:
pH = -log [H3O+] = -log (1.9 × 10^-5) = 4.72

Therefore, the correct answer is C) 4.47.

Question 15

What is the pH of a 0.020 M aqueous solution of barium hydroxide?

Accepted Answer

Barium hydroxide, Ba(OH)₂, is a strong base that dissociates completely in water to produce two hydroxide ions (OH⁻) per formula unit. Therefore, a 0.020 M solution of Ba(OH)₂ produces 0.040 M OH⁻. The pOH is calculated as -log(0.040) = 1.40. The pH is then 14 - 1.40 = 12.60.

Question 16

The base-dissociation constant of ethylamine (C₂H₅NH₂)is 6.4 × 10^-⁴ at 25.0 °C. The [H⁺] in a 1.4 × 10^-² M solution of ethylamine is ________ M.

Accepted Answer

The correct answer is A because the [H+] in a 1.4 × 10^-2 M solution of ethylamine can be calculated using the base-dissociation constant (Kb) and the concentration of the ethylamine solution. The Kb for ethylamine is 6.4 × 10^-4 at 25.0 °C, and the concentration of the ethylamine solution is 1.4 × 10^-2 M. Using the equation Kb = [H+][A-]/[B], where [H+] is the concentration of hydrogen ions, [A-] is the concentration of the conjugate base (ethylamine), and [B] is the concentration of the weak base (ethylamine), we can solve for [H+]. Plugging in the values for Kb and [B], we get: 6.4 × 10^-4 = [H+][1.4 × 10^-2]/[1.4 × 10^-2]. Solving for [H+], we get: [H+] = 3.7 × 4.9 × 10^-12 M.

Question 17

The acid-dissociation constant of hydrocyanic acid (HCN)at 25.0 °C is 4.9 × 10^-¹⁰. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN)?

Accepted Answer

The correct answer is A because the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN) is 11.00. This is because NaCN is a weak base that dissociates in water to produce OH- ions, which increase the pH of the solution.

Question 18

An aqueous solution of ________ will produce a basic solution.

Accepted Answer

Na₂SO₃ is a salt of a strong base (NaOH) and a weak acid (H₂SO₃). When dissolved in water, it hydrolyzes to form OH⁻ ions, making the solution basic.

Question 19

The acid-dissociation constant at 25.0 °C for hypochlorous acid (HClO)is 3.0 × 10^-⁸. At equilibrium, the molarity of H₃O⁺ in a 0.066 M solution of HClO is ________.

Accepted Answer

The equilibrium concentration of H₃O⁺ can be found using the formula for the acid-dissociation constant: Ka = [H₃O⁺][ClO⁻]/[HClO]. Assuming x is the concentration of H₃O⁺ at equilibrium, Ka = x²/(0.066 - x). Solving for x using Ka = 3.0 × 10⁻⁸ gives x ≈ 4.4 × 10⁻⁵ M.

Question 20

An aqueous solution of ________ will produce an acidic solution.

Accepted Answer

NH4I will produce an acidic solution because NH4+ (ammonium ion) can donate a proton (H+) to water, forming NH3 and H3O+, thus increasing the acidity of the solution.

Quiz 16: Acid-Base Equilibria

An aqueous solution of ________ will produce a neutral solution.

Hydrochloric acid is a strong acid. This means that ________.

A 0.1 M aqueous solution of ________ will have a pH of 7.0 at 25.0 °C. LiF RbBr NaClO₄ NH₄Cl

Calculate the pH of a 0.500 M aqueous solution of NH₃. The K_b of NH₃ is 1.77 × 10^-⁵.

In which of the following aqueous solutions does the weak acid exhibit the highest percentage ionization?

A 1.0 × 10^-2 M aqueous solution of Ca(OH) ₂ at 25.0 °C has a pH of ________.

An aqueous solution contains 0.10 M HNO₃. The solution is ________.

The K_a of hydrazoic acid (HN₃) is 1.9 × 10^-⁵ at 25.0 °C. What is the pH of a 0.15 M aqueous solution of HN₃?

What is the pOH of a 0.030 M solution of barium hydroxide?

What is the concentration (in M) of hydroxide ions in a solution at 25.0 °C with pH = 4.282?

Which solution will be the most basic?

The K_a of hydrofluoric acid (HF) at 25.0 °C is 6.8 × 10^-4. What is the pH of a 0.45 M aqueous solution of HF?

In which of the following aqueous solutions does the weak acid exhibit the lowest percentage ionization?

The K_a of hypochlorous acid (HClO) is 3.0 × 10^-⁸ at 25.0 °C. Calculate the pH of a 0.0385 M hypochlorous acid solution.

What is the pH of a 0.020 M aqueous solution of barium hydroxide?

The base-dissociation constant of ethylamine (C₂H₅NH₂) is 6.4 × 10^-⁴ at 25.0 °C. The [H⁺] in a 1.4 × 10^-² M solution of ethylamine is ________ M.

The acid-dissociation constant of hydrocyanic acid (HCN) at 25.0 °C is 4.9 × 10^-¹⁰. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN) ?

An aqueous solution of ________ will produce a basic solution.

The acid-dissociation constant at 25.0 °C for hypochlorous acid (HClO) is 3.0 × 10^-⁸. At equilibrium, the molarity of H₃O⁺ in a 0.066 M solution of HClO is ________.

An aqueous solution of ________ will produce an acidic solution.

Quiz 16: Acid-Base Equilibria

An aqueous solution of ________ will produce a neutral solution.

Hydrochloric acid is a strong acid. This means that ________.

A 0.1 M aqueous solution of ________ will have a pH of 7.0 at 25.0 °C. LiF RbBr NaClO4 NH4Cl

Calculate the pH of a 0.500 M aqueous solution of NH3. The Kb of NH3 is 1.77 × 10-5.

In which of the following aqueous solutions does the weak acid exhibit the highest percentage ionization?

A 1.0 × 10-2 M aqueous solution of Ca(OH) 2 at 25.0 °C has a pH of ________.

An aqueous solution contains 0.10 M HNO3. The solution is ________.

The Ka of hydrazoic acid (HN3) is 1.9 × 10-5 at 25.0 °C. What is the pH of a 0.15 M aqueous solution of HN3?

What is the pOH of a 0.030 M solution of barium hydroxide?

What is the concentration (in M) of hydroxide ions in a solution at 25.0 °C with pH = 4.282?

Which solution will be the most basic?

The Ka of hydrofluoric acid (HF) at 25.0 °C is 6.8 × 10-4. What is the pH of a 0.45 M aqueous solution of HF?

In which of the following aqueous solutions does the weak acid exhibit the lowest percentage ionization?

The Ka of hypochlorous acid (HClO) is 3.0 × 10-8 at 25.0 °C. Calculate the pH of a 0.0385 M hypochlorous acid solution.

What is the pH of a 0.020 M aqueous solution of barium hydroxide?

The base-dissociation constant of ethylamine (C2H5NH2) is 6.4 × 10-4 at 25.0 °C. The [H+] in a 1.4 × 10-2 M solution of ethylamine is ________ M.

The acid-dissociation constant of hydrocyanic acid (HCN) at 25.0 °C is 4.9 × 10-10. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN) ?

An aqueous solution of ________ will produce a basic solution.

The acid-dissociation constant at 25.0 °C for hypochlorous acid (HClO) is 3.0 × 10-8. At equilibrium, the molarity of H3O+ in a 0.066 M solution of HClO is ________.

An aqueous solution of ________ will produce an acidic solution.

A 0.1 M aqueous solution of ________ will have a pH of 7.0 at 25.0 °C. LiF RbBr NaClO₄ NH₄Cl

Calculate the pH of a 0.500 M aqueous solution of NH₃. The K_b of NH₃ is 1.77 × 10^-⁵.

A 1.0 × 10^-2 M aqueous solution of Ca(OH) ₂ at 25.0 °C has a pH of ________.

An aqueous solution contains 0.10 M HNO₃. The solution is ________.

The K_a of hydrazoic acid (HN₃) is 1.9 × 10^-⁵ at 25.0 °C. What is the pH of a 0.15 M aqueous solution of HN₃?

The K_a of hydrofluoric acid (HF) at 25.0 °C is 6.8 × 10^-4. What is the pH of a 0.45 M aqueous solution of HF?

The K_a of hypochlorous acid (HClO) is 3.0 × 10^-⁸ at 25.0 °C. Calculate the pH of a 0.0385 M hypochlorous acid solution.

The base-dissociation constant of ethylamine (C₂H₅NH₂) is 6.4 × 10^-⁴ at 25.0 °C. The [H⁺] in a 1.4 × 10^-² M solution of ethylamine is ________ M.

The acid-dissociation constant of hydrocyanic acid (HCN) at 25.0 °C is 4.9 × 10^-¹⁰. What is the pH of an aqueous solution of 0.050 M sodium cyanide (NaCN) ?

The acid-dissociation constant at 25.0 °C for hypochlorous acid (HClO) is 3.0 × 10^-⁸. At equilibrium, the molarity of H₃O⁺ in a 0.066 M solution of HClO is ________.