1. Unit 14: Acids & Bases
Chapter 19

2. Review: Naming an Acid Binary acids (H + nonmetal):
hydro ______ic acid
Ternary acids (H + polyatomic ion):
–ate ions: _________ic acid
–ite ions: _________ous acid
Name the following acids:
HBr
H2SO3
H3PO4
Write the formulas for the following acids:
Hydrosulfuric acid
Nitrous acid
Chromic acid

3. Definition of Bronsted-Lowry Acid
A chemical species that is able to lose or "donate" a hydrogen ion (aka proton because the H+ contains no electrons or neutrons) 
Acid loses a hydrogen ion

4. Properties of Acids Taste sour Corrosive Feel watery
Are electrolytes: conduct an electrical current by forming H+ ions in solution
pH < 7

5. Review: Naming a Base Formula is name + “hydroxide”: Metal + OH-
Ammonium + OH-
Name the following bases:
NaOH
NH3
Ca(OH)2
Write the formulas for the following bases:
Magnesium hydroxide
Aluminum hydroxide
Lithium hydroxide 5

6. Definition of Bronsted-Lowry Base
A chemical species that is able to gain or "accept" a hydrogen ion (aka proton because the H+ contains no electrons or neutrons) 
Base gains a hydrogen ion

7. Properties of Bases Taste bitter Corrosive Feel slippery
Are electrolytes: conduct an electrical current by forming OH- ions in solution
pH > 7 7

8. Indicators
Indicators: organic substances that change colors in an acid or a base (sometimes paper, sometimes liquids)
Acids turn…
Litmus paper – red
Phenolphthalein – clear
Universal indicator – red/orange
Bases turn…
Litmus paper – blue
Phenolphthalein – pink
Universal indicator – blue

9. Household Items & the pH Scale

10. pH and pOH Scale Measured on a numeric scale from 0-14
This scale number indicates ion concentration of a solution
It is much easier to work numbers 0-14 than with than the actual range of 1 to 10–14 ( )
In an acidic solution, [H+] > [OH-]
In a basic solution, [H+] < [OH-]
pH + pOH = 14 pH
pOH
Stands for “power of hydrogen”
Stands for “power of hydroxide”
Shows the [H+] in a solution
Shows the [OH-] in a solution
pH = -log[H+]
pOH = -log[OH-]

11. pH and pOH Scale
[H+] and [OH-] are inverses: the exponents always add up to -14
Ex: If [H+] = 1.0x10-3M, then [OH-] = 1.0x10-11M

12. pH and pOH Calculations
Notice the relationship between concentration and the pH / pOH value:
Toothpaste has a hydrogen ion concentration of 10–10M, so its pH is 10.
pH = -log[10-10] = 10
Pure water, which is neutral, has a pH of 7. That means its hydrogen ion concentration is 10–7M.
7 = -log[H+] ; [H+] = 10-7

13. pH & pOH Practice
In a NaOH solution the pH = 11. What is the [H+] of the solution?
If a substance’s pH = 3, what is the pOH?
Find the pH and pOH of a 0.1M HNO3 solution.
If the [H+] = 1x10-4M, what is the [OH-]? What is the pH and pOH?
11 = -log[H+] ; [H+] = M
3 + pOH = 14 ; pOH = 11
pH = -log[0.1] = 1
1 + pOH = 14 ; pOH = 13
1x [OH-] = 1x10-14 ; [OH-] = 1x10-10
pH = -log[1x10-4] = 4 & pOH = -log[1x10-10] = 10
(once you get pH, you can just subtract from 14 to get pOH) 13

14. Strength of Acids and Bases
Determined by how much they ionize (dissociate) in water
Strong – ionize 100% in water
Weak – only partially ionize in water
Complete dissociation - all HCl compounds have separated into H+ and Cl- ions
Partial dissociation - some HNO2 compounds have separated into H+ and NO2- ions, while some remain together

15. Strength of Acids and Bases
The terms weak and strong are used to compare the strengths of acids and bases
The terms dilute and concentrated are used to compare the concentration of solutions
They do not mean the same thing!
The combination of strength and concentration ultimately determines the behavior of the acid or base.

16. Strength of Acids and Bases
Strong Acids:
Only HNO3, HI, HBr, HCl, H2SO4, HClO4
Remember: NO, I Brought Claude SOme ClOthes
All other acids are weak, and remain in equilibrium
Ex: HNO2 ↔ H+ + NO2-
Strong Bases:
Group I or II metals
Ex: NaOH, Mg(OH)2…etc.
All other bases are weak, and remain in equilibrium
Ex: NH3 + H2O ↔ NH4+ + OH-

17. Conjugate Acids & Bases
Conjugate acids are formed when a base accepts a proton (H+)
Conjugate bases are formed when an acid donates a proton (H+)

18. Conjugate Strength Example: Strong Acid = weak conjugate base
Strong Base = weak conjugate acid
Weak Acid = strong conjugate base
Weak Base = strong conjugate acid
Example:
HCl + NH3 → Cl NH4+
(strong acid) (weak base) (weak conjugate base) (strong conjugate acid)

19. Conjugate Practice
Label the acid (A), base (B), conjugate acid (CA) & conjugate base (CB).
NH3 + HNO3 → NH4+ + NO3-
CH3OH + NH2- → CH3O- + NH3
OH- + H3O+ → H2O + H2O
NH2- + H2O → NH3 + OH-
B A CA CB
A B CB CA
B A CA CB
B A CA CB

20. Neutralization
Neutralization: the reaction of an acid and a base; products are salt and water
Example: consuming antacid products, which are basic, neutralizes stomach acid 20

21. Neutralization
Example: sodium hydroxide (base) and hydrochloric acid (acid) react to form sodium chloride (salt) and water.

22. Neutralization Practice
Neutralizations are double displacement reactions!
Practice predicting products (always a salt and water):
Example #1
__Ca(OH)2 + __H3PO4 → ?
Example #2
__Fe(OH)2 + __HBr → ?
__Ca(OH)2 + __H3PO4 → __Ca3(PO4)2 + __H2O
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O
__Fe(OH)2 + __HBr → __FeBr2 + __H2O
Fe(OH)2 + 2HBr → FeBr2 + 2H2O 22

23. Titration
Titration – determining the concentration of a base by using an acid whose concentration is known.
1. An indicator (phenolphthalein) is added to the standardized acid (acid of known concentration).
2. The unknown base is added until the solution is neutralized and reaches the equivalence point (where [H+] is equal to [OH-]).
3. Adding one more drop of base changes the color of the solution to pink. This is called the endpoint.
* The equivalence point is not necessarily the midpoint, or the point where pH = 7

24. Titration Calculations
MaVa(#H+) = MbVb(OH-)
M = concentration (molarity)
V = volume (L or mL)
(#H+ or OH-) = number of ions
Example: It took 75mL of NaOH to neutralize 50mL of 2M HCl. What is the concentration of the NaOH?
MaVa(#H+) = MbVb(#OH-)
(2M)(50mL)(1) = (x)(75mL)(1)
x = 1.33M NaOH

25. Titration Practice
Practice: It took 20mL of Ca(OH)2 to neutralize 25mL of 0.05M HCl. What is the concentration of the base?
MaVa(#H+) = MbVb(#OH-)
(0.05M)(25mL)(1) = (x)(20mL)(2)
x = M

26. Definition of Arrhenius’ Acids & Bases
Acids/bases are determined by what type of ions they produced
Arrhenius Acids produce H+ ions in solution
Monoprotic acids – have 1 ionizable hydrogen
Diprotic acids – have 2 ionizable hydrogens
Triprotic acids – have 3 ionizable hydrogens
Arrhenius Bases produce OH- in solution
Produces H+ ions in solution
Produces OH- ions in solution