1. pH scale
“power of hydrogen”

2. Scale Scale from 0-14 Stops halfway at 7 Measures H+ concentration
pH= -log (H+)

3. Low pH (acids) 0-6 we find acids
Lower the number the stronger the acid
Greater amount of H+ ions
0 is a stronger acid than 6

4. 7 Halfway on the scale Considered neutral (Neither acid or base)
Equal amounts of H+ and OH- ions
Often achieved by neutralization reactions

5. High pH 8-14 Higher then number, stronger the base
Greater number of OH- ions (pOH)
14 is stronger than 13
pH + pOH = 14
If –log (H+) = 5, what is the pH of the base? 9

6. Based on 10 The scale is based on power of 10 Ex.
pH of a 1 is 10x more acidic than 2
14 is 100x more basic than 12
pH changes from 6 to 2, what happens to acidity?
6-2 =4
10,000 x more acidic

7. pH Indicators

8. Table M
Substance that loses or gains protons which cause a color change
Found on Table M
Each indicator measure for a specific range in pH

9. Example
A solution has a pH of What color would the solution be if you added
Bromthymol Blue
blue
Thymol Blue
yellow

10. Example
Unknown solution turns the indicator phenolphthalein pink? What is the pH?
In the range , closer to 10