pH and pOH Mastery

The pH value of a solution is changed from 6.0 to 4.0. Which phrase describes the change in the hydronium ion concentration of the solution?

• decreased by a factor of 2

• increased by a factor of 2

• decreased by a factor of 100

• increased by a factor of 100

A tenfold increase in hydronium ion concentration is represented by

• a decrease of one unit of pH

• a decrease of 10 units of pH

• an increase of one unit of pH

• an increase of 10 units of pH

Solution A has a pH value of 2.0 and solution B has a pH value of 4.0. How many times greater is the hydronium ion concentration in solution A than the hydronium ion concentration in solution B?

• 10

• 2

• 100

• 4

Which solution has the highest pH?

• A

• B

• C

• D

When the concentration of hydrogen ions in a solution is decreased by a factor of ten, the pH of the solution

• increases by 1

• increases by 10

• decreases by 1

• decreases by 10

Compared to a 1.0-liter aqueous solution with a pH of 7.0, a 1.0-liter aqueous solution with a pH of 5.0 contains

• 10 times more hydronium ions

• 100 times more hydronium ions

• 10 times more hydroxide ions

• 100 times more hydroxide ions

Which statement describes characteristics of a 0.01 M KOH(aq) solution?

• The solution is acidic with a pH less than 7.

• The solution is acidic with a pH greater than 7.

• The solution is basic with a pH less than 7.

• The solution is basic with a pH greater than 7.

When the pH of an aqueous solution is changed from 1 to 2, the concentration of hydronium ions in the solution is

• decreased by a factor of 2

• decreased by a factor of 10

• increased by a factor of 2

• increased by a factor of 10

Which statement correctly describes a solution with a pH of 9?

• It has a higher concentration of H₃O⁺ than OH^-

• It has a higher concentration of OH^- than H₃O⁺

• It has a equal concentration of H₃O⁺ than OH^-

Which of these pH numbers indicates the highest level of acidity?

• 5

• 8

• 10

• 12