1. Acids & Bases

2. Properties ACIDS BASES electrolytes  electrolytes sour taste
bitter taste
turn litmus red
turn litmus blue
react with metals to form H2 gas
slippery feel
vinegar, soda, apples, citrus fruits
ammonia, lye, antacid, baking soda

3. Acid and Bases

4. Acid and Bases

5. Svante Arrhenius ( )

6. HCl + H2O  H3O+ + Cl– Arrhenius Acids – +
Arrhenius - In aqueous solution…
Acids form hydrogen ions (H+) [hydronium ions (H3O+)]
HCl + H2O  H3O+ + Cl– H Cl O – +
hydrogen ions (H+) = [hydronium ions (H3O+)] = also called a proton
acid

7. Acids -- Example Hydrochloric Acid
Forms Hydrogen Ions (H+) in solution
Forms Chloride ions (Cl-) in solution/ water
hydrogen ions (H+) = [hydronium ions (H3O+)] = proton

8. Polyprotic - an acid with more than one H+
Acids
Polyprotic - an acid with more than one H+
Monoprotic acids
Diprotic acids
Triprotic acids
H3PO4
HCl
H2SO4
HC2H3O2
H2CO3
HNO3

9. NaOH + H2O  Na+ + OH- Arrhenius Bases
Arrhenius - In aqueous solution…
Bases form hydroxide ions (OH-)
NaOH + H2O  Na+ + OH-

10. NaOH + H2O  Na+ + OH-

11. Some Common Bases KOH potassium hydroxide liquid soap
NaOH sodium hydroxide lye
KOH potassium hydroxide liquid soap
Ba(OH)2 barium hydroxide stabilizer for plastics
Mg(OH)2 magnesium hydroxide “MOM” Milk of
magnesia
Al(OH)3 aluminum hydroxide Maalox (antacid)

12. Copyright Pearson Prentice Hall
Acids, Bases, and pH
The pH scale 
Chemists devised a measurement system called the pH scale to indicate the concentration of H+ ions in solution.
The pH scale ranges from 0 to 14.
Copyright Pearson Prentice Hall

13. pH of Common Substances
pH Scale
pH of Common Substances

14. pouvoir hydrogène (Fr.)
pH Scale 14 7
INCREASING
ACIDITY
INCREASING
BASICITY
NEUTRAL
pH = -log[H+]
pouvoir hydrogène (Fr.)
“hydrogen power”

15. pH Scale = Concentration of H+/ hydrogen ions
pH = -log[H+]
Power of hydrogen
Concentration
Of hydrogen ion (H+)
Concentration is the amount of a substance (e.g. H+) per unit volume

16. pH Scale What is the pH of HNO3 with a [H+] concentration of 0.050 M ?
pH = -log[H+]
pH = -log[0.050]
pH = 1.3
Acidic or basic?
Acidic

17. Strong vs. Weak Acids
Strong Acids: ionize completely in aqueous solutions
Hydrochloric acid (HCl)
Nitric acid (HNO3)
Sulfuric acid (H2SO4)
Weak Acids: ionize only slightly in aqueous solutions
Acetic acid (HC2H3O2)

18. Strong vs. Weak Acids

20. Strong vs. Weak Acid
Protons are hydrogen ions (H+) Negative ions– Non-metal anion

21. Strong vs. Weak Acid HA H+ + A-   H+ = hydrogen ion
A- = any acid anion
HA H+ + A-
H2O  

22. Strong vs. Weak Acids
H+ = hydrogen ion
A- = any acid anion

23. Strong vs. Weak Bases
Strong Bases: ionize completely into metal cations and hydroxide ions
Sodium Hydroxide (NaOH)
Calcium Hydroxide (Ca(OH)2)
Magnesium Hydroxide (Mg(OH)2)
Weak Bases: react with water to form hydroxide ions
Ammonia (NH3)
Not
very
soluble

24. Strong Bases
Strong Bases will completely ionize (break into ions) in water.
Sodium ion (Na+)
Hydroxide ion (OH-)

25. Weak bases Weak bases only partial ionize in water
For example, only some ammonia (NH3) becomes ammonium ion (NH4+) and only some water (H20) become hydroxide ion (OH-)

26. Concentration vs. Strength
Concentrated/Dilute = indicate how much of an acid or base is dissolved in solution
Strong/Weak = indicates how many molecules ionizes or dissociates
Is it possible to have a strong base that is only mildly basic? How?

27. Concentrated vs. Dilute

29. Concentrated vs. Dilute