1. Chapter 3: An Introduction to Organic Reactions: Acids and Bases
CH 3-1: Bronsted acids & bases; Conjugate acids & bases
Chapter Summary:
CH 3-1: Bronsted acids & bases; Conjugate acids & bases
CH 3-2: Acid/Base equilibrium; pKa’s
CH 3-3: Acid/Base reactions and mechanisms
CH 3-4: Predicting acid strength: Periodic Table trends, Hybridization, Resonance and Inductive effects
CH 3-5: Acid/Base Structure: pH vs pKa
CH 3-6: Acid-Base exchange reactions

2. Defining Bronsted Acids and Bases
A chemical species that forms hydronium ion (H3O+) in aqueous solution;
A species that gives up a proton (“H+”) to a base;
An acid may be neutral or positively charged (rarely negatively charged):
NH3
H2O
“HX”
H2SO4 HF
H3O+
NH4+
H3PO4
HCl
R-OH
HNO3
HBr
R-OH2+ HI

3. Conjugate Acid-Base Pairs
In all Acid-Base reactions, we see the formation of Conjugate Pairs that differ only in the location of an H+:
acid base
conj. base conj. acid

4. Conjugate Acid-Base Pairs
B CA
B CA
A CB
A CB

5. Defining Bronsted Acids and Bases
Bronsted Base:
A species with a lone electron pair that can “grab” (accept) a proton (H+) from an acid;
A base may be neutral or negatively charged (rarely positively charged):
NH2ˉ
HOˉ Xˉ
HSO4ˉ Fˉ
H2O
NH3
H2PO4ˉ
Clˉ
R-Oˉ
NO3ˉ
Brˉ
R-OH Iˉ
CONJUGATE BASES of the corresponding acids!