Question 1

What is the pH of a 0.75 M HNO₃solution?

Accepted Answer

The pH of a 0.75 M HNO₃ solution can be calculated using the following equation:pH = -log[H+], where [H+] is the molar concentration of hydrogen ions in the solution.For a strong acid like HNO₃, the molar concentration of hydrogen ions is equal to the molar concentration of the acid. Therefore, [H+] = 0.75 M.Substituting this value into the equation, we get:pH = -log(0.75) = 0.12Therefore, the pH of a 0.75 M HNO₃ solution is 0.12.

Question 2

What is the pOH of a 0.0085 M KOH solution?

Accepted Answer

The pOH of a solution is calculated using the formula pOH = -log[OH-]. KOH is a strong base that dissociates completely in water, so the concentration of OH- ions is the same as the concentration of KOH, which is 0.0085 M. Using the formula, pOH = -log(0.0085) = 2.07.

Question 3

What is the [OH⁻] for a solution at 25°C that has [H₃O⁺] = 2.35 × 10⁻³ M?

Accepted Answer

Using the equation for the acid dissociation constant of H₃O⁺: Ka = [H+][₃O⁺] / [H₃O⁺] We can rearrange the equation to solve for [H+]: [H+] = (Ka x [H₃O⁺]) / [₃O⁺] At 25°C, Ka for H₃O⁺ is 1.2 x 10^-2. Plugging in the given values: [H+] = (1.2 x 10^-2 x 2.35 x 10^-3) / 2.35 x 10^-3 = 1.2 x 10^-2 M Since the solution is neutral, [H+] = [OH-]. Therefore: [OH-] = 1.0 x 10^-14 / [H+] = 8.3 x 10^-13 M Now we can use the equation for the base dissociation constant of OH⁻: Kb = [OH-][OH⁻] / [OH-] Simplifying: Kb = [OH-][OH⁻] / 8.3 x 10^-13 M We can rearrange the equation to solve for [OH⁻]: [OH⁻] = (Kb x 8.3 x 10^-13 M) / [OH-] = (5.7 x 10^-6 x 8.3 x 10^-13 M) / 8.3 x 10^-13 M = 5.7 x 10^-6 M Therefore, the [OH⁻] for the solution is 5.7 x 10^-6 M, which is equivalent to 4.26 x 10^-9 mol/L. The correct answer is (C) 4.26 × 10 ⁻¹² M.

Question 4

Select the pair of substances in that an acid is listed followed by its conjugate base.

Accepted Answer

HCO3- is the conjugate base of the acid H2CO3.

Question 5

What is the pH of a 0.0035 M KOH solution?

Accepted Answer

KOH is a strong base, which completely dissociates in water to form K+ and OH- ions. The OH- ions then react with water to form H2O and OH- ions, which increases the concentration of OH- ion in solution. To find the pH of the solution, we need to find the concentration of H+ ion, which can be calculated using the equation:

Kw = [H+][OH-]

Where Kw is the ion product constant of water (1.0 x 10^-14 at 25°C).

At equilibrium, the concentration of [H+] and [OH-] are equal. Thus:

Kw = [H+]^2

[H+] = sqrt(Kw) = 1.0 x 10^-7 M

Using the equation for a strong base:

KOH + H2O → K+ + OH-

We know the concentration of KOH, so we can calculate the concentration of OH-:

[OH-] = 0.0035 M

To find the pOH:

pOH = -log[OH-] = -log(0.0035) = 2.46

Since pH + pOH = 14, the pH can be calculated as:

pH = 14 - pOH = 14 - 2.46 = 11.54

Therefore, the answer is D) 11.54.

Question 6

What is the pH of a 0.050 M HBr solution?

Accepted Answer

HBr is a strong acid and completely dissociates in water. The dissociation reaction is: HBr → H+ + Br-. Therefore, the [H+] concentration in the solution is 0.050 M. To find the pH, we use the formula: pH = -log[H+]. plugging in the value we get pH = -log(0.050) = 1.30. Therefore, the answer is C.

Question 7

What is the pH of a 0.20 M HCl solution?

Accepted Answer

The pH of a solution is calculated using the formula pH = -log[H+], where [H+] is the concentration of hydrogen ions in moles per liter. For a 0.20 M HCl solution, which fully dissociates in water, [H+] = 0.20 M. Thus, pH = -log(0.20) = 0.70.

Question 8

Select the correct relationship among the concentrations of species present in a 1.0 M aqueous solution of the weak acid represented by HA.

Accepted Answer

The answer of Select the correct relationship among the concentrations...

Question 9

What is the [OH⁻] for a solution at 25°C that has [H₃O⁺] = 8.23 × 10⁻²M?

Accepted Answer

The answer of What is the [OH⁻] for a solution...

Question 10

The hydrated Al³⁺ ion, Al(H₂O)₆³⁺, is a weak acid in water. What are the products of its reaction with H₂O?Al(H₂O)₆³⁺(aq) + H₂O(l) → ?

Accepted Answer

The hydrated Al³⁺ ion acts as a weak acid by donating a proton to water, forming Al(H₂O)₅OH²⁺ and H₃O⁺.

Question 11

What is the pH of a 0.050 M LiOH solution?

Accepted Answer

LiOH is a strong base, meaning it dissociates completely in water. The pH of a solution is calculated using the formula pH = 14 - pOH. The concentration of OH- ions from LiOH is 0.050 M, so pOH = -log[OH-] = -log(0.050) ≈ 1.3. Therefore, pH = 14 - 1.3 = 12.7.

Question 12

What is the [OH⁻] for a solution at 25°C that has pH = 4.29?

Accepted Answer

The pOH can be found using the relation pH + pOH = 14. Therefore, pOH = 14 - 4.29 = 9.71. The [OH⁻] can then be calculated using [OH⁻] = 10^−pOH = 10^−9.71 ≈ 1.9 × 10⁻¹⁰ M.

Question 13

What is the [H₃O⁺] for a solution at 25°C that has pOH = 5.640?

Accepted Answer

The answer of What is the [H₃O⁺] for a solution...

Question 14

An aqueous solution is considered to be acidic if

Accepted Answer

The answer of An aqueous solution is considered to be...

Question 15

Select the pair of substances that is not a conjugate acid-base pair.

Accepted Answer

H2S and HS- are a conjugate acid-base pair; HNO3 and NO3- are a conjugate acid-base pair; HSO4- and SO42- are a conjugate acid-base pair; NH4+ and NH3 are a conjugate acid-base pair. However, H2S and S2- are not a conjugate acid-base pair.

Question 16

What is the pOH of a 0.0250 M HI solution?

Accepted Answer

The answer of What is the pOH of a 0.0250...

Question 17

When 14.7 mL of aqueous HBr (a strong acid) was added to water, 0.482 L of a solution with a pH of 4.23 was produced. What was the molarity of the original HBr solution?

Accepted Answer

The correct answer is A because the molarity of the original HBr solution can be calculated using the formula:M1V1 = M2V2where M1 is the molarity of the original HBr solution, V1 is the volume of the original HBr solution, M2 is the molarity of the diluted solution, and V2 is the volume of the diluted solution.Substituting the given values into the formula, we get:M1(14.7 mL) = (0.482 L)(10^-3 M)M1 = (0.482 L)(10^-3 M) / (14.7 mL)M1 = 1.9 × 10^-3 M

Question 18

What is the pH of a 0.0125 M NaOH solution?

Accepted Answer

NaOH is a strong base, meaning it completely dissociates in water. The dissociation reaction is:
NaOH → Na+ + OH-
This means that the concentration of OH- ions in the solution is 0.0125 M. To find the pH, we use the equation:
pH = 14 - pOH
pOH can be found using the concentration of OH- ions:
pOH = -log[OH-] = -log(0.0125) = 1.903
Finally, we can find the pH:
pH = 14 - 1.903 = 12.097

Question 19

What is the pH of a 0.00200 M HClO₄solution?

Accepted Answer

HClO is a weak acid, so it undergoes partial ionization in water, producing H+ and ClO-. The equilibrium constant expression for this reaction is Ka=[H+][ClO-]/[HClO]. 
The dissociation constant for HClO is Ka=3.0×10^-8.
To solve, set up an ICE (Initial, Change, Equilibrium) table:

HClO(aq) + H2O(l) ⇌ H3O+(aq) + ClO-(aq)

I: 0.00200 M 0 M 0 M 0 M 
C: -x 0 x x 
E: 0.00200 - x 0 x x

Plug in the equilibrium concentrations into the expression for Ka and solve for x:

Ka=[H+][ClO-]/[HClO]
3.0×10^-8 = x^2/(0.0020 - x)
Assuming x is much smaller than 0.00200, we can approximate 0.00200 - x ≈ 0.00200, which simplifies the math.

3.0×10^-8 = x^2/0.0020
x = √(3.0×10^-8 × 0.0020) = 1.94×10^-4

pH = -log[H+] = -log(x) = -log(1.94×10^-4) = 2.699, so the answer is (C).

Question 20

Which one of the following pairs is not a conjugate acid-base pair?

Accepted Answer

The pair HCl/H S1U1P1+S1S1P0 are not a conjugate acid-base pair because HCl donates a proton to form H S1U1O1S1S1P0, not H S1U1P1+S1S1P0.

Quiz 18: Acid-Base Equilibria

What is the pH of a 0.75 M HNO₃solution?

What is the pOH of a 0.0085 M KOH solution?

What is the [OH⁻] for a solution at 25°C that has [H₃O⁺] = 2.35 × 10⁻³ M?

Select the pair of substances in that an acid is listed followed by its conjugate base.

What is the pH of a 0.0035 M KOH solution?

What is the pH of a 0.050 M HBr solution?

What is the pH of a 0.20 M HCl solution?

Select the correct relationship among the concentrations of species present in a 1.0 M aqueous solution of the weak acid represented by HA.

What is the [OH⁻] for a solution at 25°C that has [H₃O⁺] = 8.23 × 10⁻²M?

The hydrated Al³⁺ ion, Al(H₂O) ₆³⁺, is a weak acid in water. What are the products of its reaction with H₂O?Al(H₂O) ₆³⁺(aq) + H₂O(l) → ?

What is the pH of a 0.050 M LiOH solution?

What is the [OH⁻] for a solution at 25°C that has pH = 4.29?

What is the [H₃O⁺] for a solution at 25°C that has pOH = 5.640?

An aqueous solution is considered to be acidic if

Select the pair of substances that is not a conjugate acid-base pair.

What is the pOH of a 0.0250 M HI solution?

When 14.7 mL of aqueous HBr (a strong acid) was added to water, 0.482 L of a solution with a pH of 4.23 was produced. What was the molarity of the original HBr solution?

What is the pH of a 0.0125 M NaOH solution?

What is the pH of a 0.00200 M HClO₄solution?

Which one of the following pairs is not a conjugate acid-base pair?

Quiz 18: Acid-Base Equilibria

What is the pH of a 0.75 M HNO3 solution?

What is the pOH of a 0.0085 M KOH solution?

What is the [OH−] for a solution at 25°C that has [H3O+] = 2.35 × 10−3 M?

Select the pair of substances in that an acid is listed followed by its conjugate base.

What is the pH of a 0.0035 M KOH solution?

What is the pH of a 0.050 M HBr solution?

What is the pH of a 0.20 M HCl solution?

Select the correct relationship among the concentrations of species present in a 1.0 M aqueous solution of the weak acid represented by HA.

What is the [OH−] for a solution at 25°C that has [H3O+] = 8.23 × 10−2 M?

The hydrated Al3+ ion, Al(H2O) 63+, is a weak acid in water. What are the products of its reaction with H2O?Al(H2O) 63+(aq) + H2O(l) → ?

What is the pH of a 0.050 M LiOH solution?

What is the [OH−] for a solution at 25°C that has pH = 4.29?

What is the [H3O+] for a solution at 25°C that has pOH = 5.640?

An aqueous solution is considered to be acidic if

Select the pair of substances that is not a conjugate acid-base pair.

What is the pOH of a 0.0250 M HI solution?

When 14.7 mL of aqueous HBr (a strong acid) was added to water, 0.482 L of a solution with a pH of 4.23 was produced. What was the molarity of the original HBr solution?

What is the pH of a 0.0125 M NaOH solution?

What is the pH of a 0.00200 M HClO4 solution?

Which one of the following pairs is not a conjugate acid-base pair?

What is the pH of a 0.75 M HNO₃solution?

What is the [OH⁻] for a solution at 25°C that has [H₃O⁺] = 2.35 × 10⁻³ M?

What is the [OH⁻] for a solution at 25°C that has [H₃O⁺] = 8.23 × 10⁻²M?

The hydrated Al³⁺ ion, Al(H₂O) ₆³⁺, is a weak acid in water. What are the products of its reaction with H₂O?Al(H₂O) ₆³⁺(aq) + H₂O(l) → ?

What is the [OH⁻] for a solution at 25°C that has pH = 4.29?

What is the [H₃O⁺] for a solution at 25°C that has pOH = 5.640?

What is the pH of a 0.00200 M HClO₄solution?