1. Acids and Bases

2. Chapter 15 Acids and Bases 15.2 the Acids and Bases properties of water 15.3 PH- a measure of acidity

3. Acids and Bases

4. 15.2 the Acids and Bases properties of water water is a unique solvent, it can act as acid or base. In pure water, a few molecules act as bases and a few act as acids. acid(1) + base (2) ⇄ acid(2) + base (1) This is referred to as autoionization of water ( التأين الذاتي ) The equilibrium expression for this process is This special equilibrium constant is referred to as the ion-product constant for water, K w Hydronium ion ثابت الحاصل الايوني للماء At 25 °C, K w = 1.0  10 −14

5.  In pure water,  In pure water [H 3 O + ] = [OH − ] (neutral)  In acidic solution:  In basic solution The Ion-Product of Water

6. Example 15.2 a: Calculate the [H + ] ions in ammonia, [OH - ] =0.0025 M? Solution: [H + ] = 4 x10 -12 ; [OH - ] =2.5 x 10 -3 [H + ] < [OH - ] the solution is basic

7. Example 15.2 b: Calculate the [OH - ] ions in 1.3 M HCl ? Solution: [H + ] = 1.3; [OH - ] =7.7 x 10 -15 [H + ] > [OH - ] the solution is Acidic

8. pH of a solution: is the negative logarithm (base- 10) of the hydrogen ion (hydronium ion) concentration. In the same manner 15.3 pH-A Measure of Acidity

9. In pure water, 15.3 pH-A Measure of Acidity

10. Example 15.3 a: The [H + ] = 3.2 x 10 –4 M. The [H + ]=1.0 x 10 –3 M. What is the pH in the two occasions. Solution: Thus: pH is inversely proportional to [H + ] [H + ] increase, pH decrease >>> more acidic

11. Solution: Thus: pH is inversely proportional to [H + ] Example 15.3 b: The [H + ] = 0.76M, in nitric acid solutions What is the pH? [H + ] increase, pH decrease >>> more acidic

12. pH Range 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Neutral [H + ] > [OH - ] [H + ] = [OH - ] [OH - ]>[H + ] AcidicBasic Increase the acidity Increase the basicity pH is inversely proportional to [H + ] pH = pOH = 7pH > 7 pH < 7

13. Example 15.4 a: The pH = 4.82, What is the [H + ] of the rain water. Solution: In the calculator: Press SHEFT → log button → (-ve ) value (4.82)=

14. Example 15.4 b: The pH = 3.33, What is the [H + ] of the orange juice. Solution:

15. Example 15.5 a: The [OH - ] = 2.9 x 10 –4 M. What is the pH of the NaOH solution. Solution: OR pH = 10.46 > 7 BASIC (NaOH)

16. Example 15.5 b: The [OH - ] = 2.5 x 10 –7 M. What is the pH of the blood solution. Solution: OR pH = 7.4 ~ 7 neutral (blood)

17. Summary

18. 15.9, 15.13, 15.16, 15.18, 15.20, 15.22, 15.24, 15.26 problems