1. ACIDS AND BASES

2. EQ: What is an acid. What is a base
EQ: What is an acid? What is a base? What happens when acids and bases react?

3. DEFINITIONS Basic: Acid = tastes sour, strong smell
Base = tastes bitter, feels slippery/soapy
(Both cause burns if concentrated)

4. DEFINITIONS Arrhenius: Brønsted-Lowry: Acid = produces H+ in solution
Base = produces OH- in solution
Brønsted-Lowry:
Acid = proton donor
Base = proton acceptor

5. NEUTRALIZATION REACTIONS
HA + BOH ⟷ BA + HOH
acid + base salt + water
Example:
Nitric acid is added to potassium hydroxide:
HNO3 + KOH ⟷ KNO3 + H2O

6. Acid/Base Stoichiometry (similar to solution stoich.)
A 10 mL sample of 1.5 M hydrochloric acid requires 20 mL of sodium hydroxide to completely neutralize. What molarity is the sodium hydroxide?
“Neutralize” = react acid and base exactly so there is no excess.
HCl + NaOH ⟷ NaCl + H2O
10 mL mL
1.5 M ? M
0.01 𝐿 𝐻𝐶𝑙 𝑥 1.5 𝑚𝑜𝑙 𝐻𝐶𝑙 𝐿 𝐻𝐶𝑙 𝑥 1 𝑚𝑜𝑙 𝑁𝑎𝑂𝐻 1 𝑚𝑜𝑙 𝐻𝐶𝑙 =0.015 𝑚𝑜𝑙 𝑁𝑎𝑂𝐻
𝑀= 0.15 𝑚𝑜𝑙 𝑁𝑎𝑂𝐻 𝐿 =0.75 𝑀

7. EQ: What is a strong acid. How is [H+] and [OH-] calculated
EQ: What is a strong acid? How is [H+] and [OH-] calculated? How is pH Calculated?

8. Strong Acids & Bases (Completely Dissociate/Ionize)
HCl, HNO3, H2SO4, HClO4
HA ⟷ H+ + A-
[HA] = [H+]
BASES
LiOH, NaOH, KOH, RbOH
BOH ⟷ B+ + OH-
[BOH] = [OH-]

9. Acid/Base Equilibrium
Water autoionizes (it naturally exists both in its liquid form and its ion form
H2O ⟷ H+ + OH-
Equilibrium constant for Water (Kw); “Water Dissociation Constant”
Kw = [H+][OH-] = 1 x (experimentally determined, at 25˚C)
Can use this equation to solve for [H+] or [OH-] when you know the other

10. pH pH = - log [H+] pH < 7 ➝ Acidic pH = 7 ➝ Neutral
pOH = - log [OH-]
[OH-] = 10-pOH
pH + pOH = 14
pH < 7 ➝ Acidic
pH = 7 ➝ Neutral
(pure H2O)
pH > 7 ➝ Basic

11. What if a reaction isn’t perfectly neutralized?
100 mL of 2.0 M sodium hydroxide is combined with 75 mL of 3.0 M hydrochloric acid. What is the limiting reagent, what is the excess reagent, and what is the pH of the resulting solution?
NaOH + HCl ⟷ NaCl + H2O
0.100 𝐿 𝑁𝑎𝑂𝐻 𝑥 2.0 𝑚𝑜𝑙 𝑁𝑎𝑂𝐻 𝐿 =0.2 𝑚𝑜𝑙 𝑁𝑎𝑂𝐻
0.075 𝐿 𝐻𝐶𝑙 𝑥 3.0 𝑚𝑜𝑙 𝐻𝐶𝑙 𝐿 =0.225 𝑚𝑜𝑙 𝐻𝐶𝑙
Mole Ratio: 1 mol NaOH per 1 mole HCl
NaOH is limiting, HCl is in excess
0.025 mol of HCl remains after the reaction
𝑀= 𝑚𝑜𝑙 𝐻 𝐿 𝐿 =0.143 𝑀
pH = - log (0.143M) = 0.845

12. EQ: What is a titration? How is the equivalence point of a titration determined?

13. Titrations
Method used to determine the unknown concentration of an acid or base
The systematic addition of a base to an acid (or visa versa)
The concentration of the titrant used must be known
The volume of titrant required to reach equivalence point is used to determine the unknown concentration of acid or base.

14. Titrations Equivalence Point: Indicators:
The point at which all of the acid present has reacted exactly with all of the base (aka “perfectly neutralized”)
Indicators:
A chemical added to a titration that will change the color of the solution at the equivalence point.
Common Indicator = Phenolphthalein (PHTH)
Colorless in acid, Pink in base