Organic Chemistry Chapter 2

Bronsted-Lowry Acid/Bases

Describes acidity based on protons- positively charged H ions

BL Acid: donates proton (H⁺)

BL Base: accepts proton (H⁺)

BL Acid and Bases Reactions

Proton transfer reactions- result in transfer of proton from acid to base

Key to All Organic Reactions!

Electron-rich species react with electron-poor species

(Electron-rich bases donate e pair to the acids)

How to Identify Acids-Bases?

1. Know the common ones! Some examples.

a. Acids – HCl, H2SO4

b. Bases – –OH

2. When only one starting material contains an H, it’s the acid.

3. If only one starting material has a lone pair of electrons or a π-bond, it’s the base.

4. Starting material with net (+) charge is the acid.

5. Starting material with net (-) charge is usually the base.

Acid Strength

Tendency of an acid to donate a proton

(stronger the acid, the larger the Ka, the equilibrium lies to the right)

(as pKa decreases, acidity increases)