Ch. 17 - Acids & BasesCh. 17 - Acids & Bases

II. Strength of Acids & Bases (p.474-477)

Strong vs. Weak pH

A. Strong vs. WeakA. Strong vs. Weak

Strong Acid/BaseStrong Acid/Base• 100% ions in water• strong electrolyte• HCl, HNO3, NaOH, LiOH

Weak Acid/BaseWeak Acid/Base• few ions in water• weak electrolyte• HC2H3O2, NH3

- +

- +

B. pH ScaleB. pH Scale

0

7INCREASING

ACIDITY NEUTRALINCREASING

BASICITY

14

pHpH• a measure of the concentration of

H3O+ ions in solution• measured with a pH meter or an

indicator with a wide color range

B. pH ScaleB. pH Scale

pH of Common SubstancespH of Common SubstancespH of Common SubstancespH of Common Substances

Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA?

ConcepTestConcepTest

A B

Is the following statement TRUE or FALSE?

• A strong acid has a lower pH than a weak acid.

• FALSE - Strong/weak refers to amount of ionization whereas pH refers to concentration of H+.

ConcepTestConcepTest