1. Topic: pH and Indicators
List the following as an acid or base
HCl b) KOH c) CH3COOH d)HF
Which of the following would have a pH greater than 7
a) HCl b) CH3OH c) KOH d) NaCl

2. pH scale power (or potential) of Hydrogen Ranges from measures H+ concentration [H+] the more H+, the more acidic the solution

3. Acid, Base, or Neutral H+1 > OH-1 OH-1 > H+1 [H+] = [OH-]
Neutral solution: pH = 7
Acidic solution: pH LESS THEN 7
Basic solution: pH GREATER THEN 7
H+1 > OH-1
OH-1 > H+1

4. How to safely test pH NEVER “taste” Instruments – use a pH meter
See if the substance reacts with a metal other than Cu, Ag, or Au
Indicators – use a series of indicators

5. Indicator
substance that changes color over narrow pH range

6. What color would the following indicators be in a neutral solution?
yellow
green
colorless
purple
blue
yellow

7. Use several indicators to narrow down pH range of substance
Ex: Three samples of the same solution are tested, each with a different indicator. All three indicators, bromthymol blue, bromcresol green and thymol blue, appear blue
The pH of the solution must be greater than_____

8. Practice using table M 1. What indicator is yellow with a pH 9. 8 2
Practice using table M 1. What indicator is yellow with a pH Which indictor is blue with a pH of 5.6
0-3.0
Orange
Green
Pink
Purple
4.5-14
7.7-14
8.4-14
0-3.7
5.5-14
9.7-14