Here’s a explanation of the physical properties of alcohols–
1. State and Appearance
- Lower alcohols (like methanol, ethanol) are colorless liquids with a mild smell.
- Higher alcohols may be waxy solids.
2. Boiling Point
- Alcohols have higher boiling points than alkanes, ethers, and aldehydes of similar molecular mass.
- This is due to hydrogen bonding between –OH groups.
3. Solubility in Water
- Lower alcohols (methanol, ethanol, propanol) are highly soluble in water because they form hydrogen bonds with water molecules.
- Solubility decreases as the length of the hydrocarbon chain increases, since the non-polar part dominates.
4. Density
- Most alcohols are less dense than water.
- Exceptions: Some higher alcohols have densities slightly greater than water.
5. Odor and Taste
- Many alcohols have a characteristic odor (ethanol has a pleasant smell, methanol is pungent).
- Ethanol is drinkable in small amounts, while methanol is toxic.
6. Volatility
- Lower alcohols are volatile, but volatility decreases as molecular mass increases.
In summary:
Alcohols are colorless liquids or solids, soluble in water (if small-chain), have higher boiling points due to hydrogen bonding, are generally less dense than water, and show decreasing volatility with chain length.