10.4 pH and the pH Scale

Which statement describes the concentration of hydrogen ions and hydroxide ions in pure water?

• More hydrogen ions are present

• More hydroxide ions are present

• Equal amounts of both ions are present.

In an acidic solution

• The hydroxide ion concentration is greater.

• The hydrogen ion concentration is greater.

• The are equal amounts of hydrogen and hydroxide ions.

In an basic solution

• The hydroxide ion concentration is greater.

• The hydrogen ion concentration is greater.

• The are equal amounts of hydrogen and hydroxide ions.

A substance with a pH of 9 is

• acidic

• basic

• neutral

A substance with a pH of 4 is

• acidic

• basic

• neutral

A substance with a pH of 7 is

• acidic

• basic

• neutral

When the pH increases from 3 to 4 the hydrogen ion concentration

• increases

• decreases

• remains the same

When the pH decreases from 11 to 9 the hydrogen ion concentration

• increases

• decreases

• remains the same

When the pH changes from 5 to 7

• hydrogen ion concentration decrease by 10

• hydrogen ion concentration decrease by 100

• hydrogen ion concentration decrease by 2

• hydrogen ion concentration decrease by 20

When the hydrogen ion concentration decreases by a factor of 1000,

the pH changes from

• 3 to 4

• 3 to 5

• 3 to 6

• 3 to 7