1. What is the pH of a solution with a 2.20 * 10-8 M hydroxide ion concentration? 0.342 6.00 6.34 7.66

2. What are the concentrations of hydroxide and hydronium ions in a solution with a pH of 10.2?

1.4 * 10-4 M H3O + and 7.1 * 10-11 M OH-

3.8 * 10-6 M H3O + and 2.6 * 10-9 M OH-

8.3 * 10-9 M H3O + and 1.2 * 10-6 M OH-

6.3 * 10-11 M H3O + and 1.6 * 10-4 M OH-

3. A solution at 25 degrees Celsius has a pOH of 6.42. What is the pH of this solution? 0.842 3.80 5.59 7.58

4. What is the pH of a solution with a concentration of 4.2 * 10-5 M H3O+?

2.31 4.38 5.62 6.87

5. Water is an amphoteric substance because it can receive and donate hydrogen ions. True False

6. The concentration of hydronium ions is greater than 1 * 10-7 for basic solutions. True False

1. 6.34.

2. 6.3 x 10⁻¹¹ M H₃O⁺ and 1.6 * 10⁻¹⁰ M OH⁻.

3. 7.58.

4. 4.38.

5. True.

6. True.

Explanation:

1. What is the pH of a solution with a 2.20 * 10⁻⁸ M hydroxide ion concentration?

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

[OH⁻] = 2.20 * 10⁻⁸ M.

∴ [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴ / (2.20 * 10⁻⁸ M) = 4.54 * 10⁻⁷ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log (4.54 * 10⁻⁷ M) = 6.34.

2. What are the concentrations of hydroxide and hydronium ions in a solution with a pH of 10.2?

∵ pH = - log[H₃O⁺]

∴ 10.2 = - log[H₃O⁺].

∴ log[H₃O⁺] = - 10.2.

∴ [H₃O⁺] = 6.31 x 10⁻¹¹ M ≅ 6.3 x 10⁻¹¹ M.

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

[H₃O⁺] = 6.31 x 10⁻¹¹ M.

∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴ / (6.31 x 10⁻¹¹ M) = 1.58 * 10⁻⁴ M ≅ 1.6 * 10⁻¹⁰ M.

So, the right choice is: 6.3 x 10⁻¹¹ M H₃O⁺ and 1.6 * 10⁻¹⁰ M OH⁻.

3. A solution at 25 degrees Celsius has a pOH of 6.42. What is the pH of this solution?

∵ pH + pOH = 14.

∵ pOH = 6.42.

∴ pH = 14 - pOH = 14 - 6.42 = 7.58.

4. What is the pH of a solution with a concentration of 4.2 * 10⁻⁵ M H₃O⁺?

∵ pH = - log[H₃O⁺]

∵ [H₃O⁺] = 4.2 * 10⁻⁵ M.

∴ pH = - log (4.2 * 10⁻⁵ M) = 4.376 ≅ 4.38.

5. Water is an amphoteric substance because it can receive and donate hydrogen ions. True False

A Brønsted-Lowry acid is any species that is capable of donating a proton H⁺.

A Brønsted-Lowry base is any species that is capable of accepting a proton, which requires a lone pair of electrons to bond to the H⁺.

Water is amphoteric, which means it can act as both a Brønsted-Lowry acid and a Brønsted-Lowry base.

So, the answer is: True.

6. The concentration of hydronium ions is greater than 1 * 10⁻⁷ for basic solutions. True False

For a solution to be acidic, The concentration of hydronium ions is smaller than 1 * 10⁻⁷, that pH of the solution will be lower than 7.

For a solution to be basic, The concentration of hydronium ions is greater than 1 * 10⁻⁷, that pH of the solution will be higher than 7.

So, the answer is: True.