Boiling Point Hierarchy (Similar Molar Mass)
Carboxylic acid > Alcohol > Aldehyde/Ketone > Ether ≈ Alkane
H-bonding + dimerization > H-bonding > Dipole-dipole > LDF only
Factors Affecting Physical Properties
| Factor | Effect on BP | Reason |
|---|---|---|
| ↑ Chain length | Higher | More electrons → stronger LDFs |
| Branching | Lower | Smaller surface area → weaker LDFs |
| H-bonding groups (–OH, –NH₂) | Much higher | Strong IMFs between molecules |
Solubility
Short-chain alcohols (methanol, ethanol) are soluble in water. The –OH group forms H-bonds with water. As the hydrocarbon chain grows, the non-polar tail dominates and solubility decreases.