Class 12 Chemistry Notes – Physical Properties of Alcohols

Physical state:-

1.  At room temp, lower alcohols are colourless liquids
2. The higher members are colourless odourless oxy solids

Boiling points:-

Boiling points of alcohols use much higher than aliphatic hydrocarbons and halo alkanes

Reason of forms hydrogen bonding and exists as associate molecules

The boiling points decreases with branching due to a corresponding decrease surface area. In the order primary > secondary > tertiary

Solubility: –

The lower alcohols are highly soluble in water with increase in molecular mass the solubility gets decrease.

→ Solubility extent depends upon capability of its molecule to form Hydrogen bond with water

→ Molecule mass increases, hydrocarbon part becomes large, it resist the formation of (—H) bond and solubility decreases.

Ex.            Alcohol                        Solubility

N-Butyl alcohol                 7.9

N-Pentyl alcohols             2.3

Physiological action :-

Methanol is poisonous and not good for drinking purpose

On the other hand ethanol has intoxicating effect and is used for drinking purposes.

Class 12 Chem Alcohols, Phenols and Ethers All Topics Notes Class 12 Chemistry All Chapter Notes