Solutions & Colligative Properties: Concept Map and Visual Overview

Concept Hierarchy

Osmosis — Key Image

Osmosis — movement of solvent across semipermeable membrane from low to high solute concentration Solvent flows from lower osmotic pressure (dilute) to higher osmotic pressure (concentrated). Osmotic pressure π = iCRT. Reverse osmosis: apply P > π to purify water.

Comparative Table: Electrolytes and Colligative Effects (0.1 m solutions)

Solute	i	$\Delta Tf$ (K) = i × 1.86 × 0.1	Relative Order
Glucose ( $C_{6}H_{12}O_{6}$ )	1	0.186	Lowest
NaCl	2	0.372	Second
$CaCl_{2}$	3	0.558	Third
$AlCl_{3}$	4	0.744	Highest

Kf and Kb for Common Solvents

Solvent	Kb	Kf
Water	0.52	1.86
Benzene	2.53	5.12
Acetic acid	3.07	3.90
Chloroform	3.63	4.68
Camphor	5.95	40.0

Camphor's exceptionally large Kf (40 K·kg/mol) makes it ideal for determining molar masses by the Rast method. Even milligram-scale samples give measurable freezing point depressions.