1. Acids and Bases

2. Acids Tart or Sour taste Electrolytes
React with bases to form H2O & a salt
Produces H+ (hydrogen ions) when dissolved in H2O
General form - HX

3. Bases Bitter Taste Feel slippery Electrolytes
React with acids to form H2O & a salt
Produces OH– (hydroxide ions) when dissolved in H2O

4. Naming Acids Identify name of anion
Anion ends in “-ide”, acid name begins with “hydro” – (Cl - chloride)
Stem of anion ends in “-ic”, followed by “acid”
HCl  Hydrochloric Acid
H2S  Hydrosulfuric Acid

5. Naming Acids cont. Anion ends in “-ate” – (SO4 - sulfate)
Stem of the anion ends in “-ic”, followed by “acid”
H2SO4  Sulfuric Acid
HNO3  Nitric Acid

6. Naming Acids cont. Anion ends in “-ite” – (SO3 - sulfite)
Stem of the anion ends in “-ous”, followed by “acid”
H2SO3  Sulfurous Acid
HNO2  Nitrous Acid

7. Write the Formula Chloric Acid Hydrobromic Acid Phosphorous Acid
Carbonic Acid
HClO3
HBr
H3PO3
H2CO3

8. Naming Bases Ionic compounds Name as an ionic compound
Name of cation followed by anion
NaOH  Sodium Hydroxide
Ca(OH)2  Calcium Hydroxide

9. Water Water molecules are highly polar
Continuous motion
Occasionally, collisions between H2O molecules are energetic enough to transfer a H+ -- Self-ionization
H2O + H2O  H3O+ + OH-
H3O+ – Hydronium Ion

10. Water (cont.) Self-ionization reaction Pure H2O at 25 °C
H2O(l)  H+(aq) + OH-(aq)
Pure H2O at 25 °C
[H+] = [OH-] = 1.0 x 10-7M
Ion-product constant for water (Kw)
Kw = [H+] x [OH-] = 1.0 x 10-14M2

11. Acidity (H+)/Basicity (OH-)
Acidic solutions – [H+] is greater than [OH-]
[H+] is greater than 1.0 x 10-7M
[OH-] is less than 1.0 x 10-7M
Basic solutions – [H+] is less than [OH-]
[H+] is less than 1.0 x 10-7M
[OH-] is greater than 1.0 x 10-7M

12. Acidic or Basic Solution? Not all solutions are neutral!!! [H+] = [OH-]
Acidic soln – release H+
HCl(aq)  H+(aq) + Cl-(aq)
[H+] > 1.0 x 10-7M
[H+] > [OH-]
Basic Soln – release OH-
NaOH(aq)  Na+(aq) + OH-(aq)
[H+] < 1.0 x 10-7M
[H+] < [OH-]

13. Classify – Acidic, Basic, Neutral
[H+] = 1.0 x 10-9M
[OH-] = 2.0 x 10-5M
If [H+] = 1.0 x 10-4M, is the solution acidic, basic or neutral?
What is the [OH-]?
Basic
Acidic
Kw = [H+] x [OH-]
[OH-] = Kw / [H+]
[OH-] = 1.0 x 10-14M2 / 1.0 x 10-4M
= 1.0 x 10-10M

14. pH Scale pH – scale used to express [H+] Ranges from 0 – 14
pH=0 Strongly acidic
pH=14 Strongly basic
pH = - log [H+]
Ex. Neutral Solution
[H+] = 1.0 x 10-7M
pH = - log (1.0 x 10-7M) = 7

15. pH cont. Calculations: [H+] > 1.0 x 10-7M [H+] = 6.0 x 10 -10M
then pH < 7 (acidic)
[H+] < 1.0 x 10-7M
then pH > 7 (basic)
Recall
[H+][OH-]= 1.0 x 10-14M
Calculations:
[H+] = 6.0 x M
Acidic or Basic?
pH = ?
[OH-] = ?

16. pOH Scale & calculations
pOH– scale used to express [OH-]
pOH = - log [OH-]
pH + pOH = 14
If pH = 6.5, calculate pOH & [OH-].
pOH = 14 – 6.5 = 7.5
[OH-]= 10-pOH = = 3.1 x 10-8M

17. Measuring pH Why – swimming pools, soil, medical (diabetes) How
1. Acid – Base indicators – change color at a specific pH
Ex. phenothalein, thymol blue …
(Pg. 590 Figure 20.8)
2. Litmus paper
3. pH meters – make rapid & accurate measurements

18. Assignment Name each acid or base:
a. HF b. KOH c. HNO3 d. H2SO4
e. HClO3 f. Al(OH)3 g. H3PO3 h. Fe(OH)3
Write the formula for each acid or base:
a. barium hydroxide b. hydroselenic acid
c. chromic acid d. hydrobromic acid
e. rubidium hydroxide f. iron(II) hydroxide
g. chlorous acid h. sulfurous acid
Identify each property as applying to an acid, a base or both.
a. bitter taste b. indicator color change
c. electrolyte d. sour taste

19. Assignment Continued
Pg. 658 – 35, 41-43
pH Worksheet