1. pH and Indicators
Chemistry
Mrs. Coyle

3. Basic
14>ph>7
Neutral
ph=7
Acidic
1<pH<7

4. Self Ionization of H2O
H2O  H+
(aq) + OH-
(aq)
Ion Product Constant K w for Water:
Kw= [H+
] x [OH-
] =1.0 x 10 -14

5. For pure H2O
[H+
] = [OH-
] = 1.0 x 10-7
M

6. pH
• 1909 Soren Sorensen (Danish)
pH=-log[H+
]
What is the pH of pure water?

7. Ex 1: Find the pH for [H+
]=10-3
M
• Answer: pH=3

8. Ex 2: Find the pH for [H+
]=5x10-3
M
• Answer: pH=2.3

9. Finding [H+
] from pH
• [H+
]= 10-pH

10. Ex 3: Find the [H+
] for pH=5
• Answer: [H+
] = 10-5
M

11. Ex 4: Find the [H+
] for pH=5.8
• [H+
]= 10-pH
• Answer: [H+
] = 1.6x10-6
M

12. pOH
pH=-log[H+
]
pH + pOH=14

13. Basic(Alkaline)
Solutions
Acidic
Solutions
Neutral
Solutions

14. Acids
Change phenolphthalein to
colorless.

15. Acids
• Turn litmus paper
from blue to red.

16. Bases
Change phenolphthalein
to pink.