Alkyl halides or halo alkanes are compounds in which a halogen is bonded to an alkyl group. They have the general formula RX (where R is alkyl group CnH2n+1) X is halogen atom.

Alkyl halides are classified as primary, secondary and tertiary alky halides

depending on whether the halogen atom is attached to a primary, secondary or tertiary carbon atom respectively.

Aromatic halogen compounds or halo arenes are the halogen compounds which contain at least one aromatic ring. Halogen derivatives of aromatic compounds are of two types.

Aryl halides: In this type of compounds, the halogen atom is directly linked to the carbon of benzene nucleus.

Aralkyl halides: In this type of compounds halogen is linked to the carbon atom of the side chain

Boiling Points

The boiling points of haloalkanes are in the order RCl < RBr < RI. It is because with increase in size and mass of halogen atom the magnitude of Vander Waal’s forces of attraction increases. Among isomeric alkyl halides, the boiling point decreases with increase in branching in alkyl group.

Solubility

Haloarenes are insoluble in water, acids or base but are soluble in organic solvents. Haloarenes are insoluble in water because they can not form hydrogen bonds with water molecules.

Density

They are all heavier than water. Their densities follow the order:

Iodo > Bromo > Chloro