University:
York University
Course:
CHEM 1000 | Chemical Structure
Academic year:

2021
Views:

319

Pages:

5
Author:

Niklas

Acids/Bases: Brønsted: Acid donors/acceptors of H+ (H+) Base acceptors/donors of H+ (H-) Lewis Acid acceptors/donors of e- Base acceptors/donors of e- Acid = H+ donor/e- acceptor Base = H+ acceptor/e- donor Equilibrium Constant (Ka): H-Cl + H2O = H3O+ + Cl- Acid Base Conj. Acid Conj. Base Donated H Accepted H Ka = [H3O+][Cl-] / [H2O][HCl] = >>> 1 Ka < 1 Left side (products favored) Ka > 1 Right side (products favored) Ka = 1 50% mix as SM, & prds "Starting Materials" "Products" X-Y -> X: Y' MO picture -> On (1) H-Cl is a mated Identify Acids/Bases (FG) What to look for? Lone pairs on heteroatoms are often bases. Act as H+ acceptors. Major product: protonation on the nitrogen atom Minor product (significant): protonation on the oxygen atom Quantifying Acidity: Ka = [conj. B][conj. A] / [A][B] pKa = -log Ka - dissociation constant Ka α 1/pKa Acids with higher pKa are weaker donors of H+. Acids with lower pKa are better donors of H+. Question: pKa of HI/HBr/HCl ~ -10 BUT... HF = +3.17 Why?