1. © Copyright Pearson Prentice Hall Slide 1 of 50 Hydrogen Ions and Acidity To test a diagnosis of diabetic coma, a doctor orders several tests, including the acidity of the patient’s blood. Results from this test will be expressed in units of pH. You will learn how the pH scale is used to indicate the acidity of a solution and why the pH scale is used. 19.2

2. © Copyright Pearson Prentice Hall Hydrogen Ions and Acidity > Slide 2 of 50 The pH Concept How is the hydrogen-ion concentration used to classify a solution as neutral, acidic, or basic? 19.2

3. Slide 3 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity The pH Concept A solution in which [H + ] is greater than 1  10 –7 M has a pH less than 7.0 and is acidic. The pH of pure water or a neutral aqueous solution is 7.0. A solution with a pH greater than 7 is basic and has a [H + ] of less than 1  10 –7 M. 19.2

4. Slide 4 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity 19.2 The pH Concept

5. Slide 5 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity The pH Concept 19.2

6. Slide 6 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity The pH Concept pH and Significant Figures 19.2

7. © Copyright Pearson Prentice Hall Hydrogen Ions and Acidity > Slide 7 of 50 Measuring pH What is the most important characteristic of an acid-base indicator? 19.2

8. © Copyright Pearson Prentice Hall Hydrogen Ions and Acidity > Slide 8 of 50 Measuring pH An indicator is a valuable tool for measuring pH because its acid form and base form have different colors in solution. 19.2

9. Slide 9 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity Measuring pH Phenolphthalein changes from colorless to pink at pH 7–9. 19.2

10. Slide 10 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity Measuring pH Universal Indicators 19.2

11. Slide 11 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity Measuring pH pH Meters 19.2

12. Slide 12 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity Measuring pH Sample Questions: A solution in which the hydroxide ion concentration is 1 x 10 -5 is a. Acidic b. Basic c. Neutral d. None of the above 19.2

13. Slide 13 of 50 © Copyright Pearson Prentice Hall > Hydrogen Ions and Acidity Measuring pH Sample Questions: Which of these solutions is most basic? a. [H+] = 1 x 10 -11 b. [OH-] = 1 x 10-4 c. [H+] = 1 x 10 -2 d. [OH-] = 1 x 10 -13 19.2

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