Physical Properties of Ether
Polar Nature of Ether
Since the electronegativity of oxygen is greater than that of carbon, ethers are
in nature. Moreover, the two C-O bonds in
ether are inclined to each other at an angle of 110°, and therefore, the two dipoles do
not cancel each other, resulting in a net dipole moment.
i.e., The dipole moment (μ) in ether ≠ 0
Boiling Point of Ether
The boiling point of ethers is lower than that of isomeric alcohols because ethers do not form H-bonds within themselves. For example, the boiling point of methoxy methane (CH3OCH3) is lower than that of ethanol (CH3CH2OH) even though both have the same formula C2H6O.
Solubility of Ether
- Lower ethers (up to three carbon atoms) are soluble in water because they form hydrogen bond with water molecules. The solubility of ethers in water decreases with increase in mass because the hydrocarbon part becomes larger and resists the formation of hydrogen bonds with water molecules.
- Ethers are fairly soluble in organic solvents such as alcohols, benzene, acetone.
Density of Ether
Ethers are lighter than water.
Question : The boiling points of ethers are much lower than those of the alcohols of comparable molar masses. Explain why?
Answer : Because ethers do not form intermolecular H-bond with themselves whereas alcohols do.