Halogenalkanes properties?

Question

What are Halogenalkanes? What type of intermolecular force do they have and like why do they have such low boiling points?

Heard the number of carbon in the chain plays a big role in this but I don’t understand how.

Answer 1

An alkane is a hydrocarbon (contains carbon and hydrogen) that has no double or triple bonds, i.e. only single bonds. A halogen is at element in group 17, i.e. F, Cl, Br, I, ..). So a halogenalkane is an alkane that has one or more of the hydrogens substituted with a halogen.

Since halogens are rather electronegative, they tend to make the original alkane more polar than it was originally, and thus the halogenalkane would have a higher boiling point than the normal alkane. If you are simply comparing halogenalkanes of different carbon length, the the longer the carbon chain, the higher will be the boiling point. The reason: longer carbon chain means greater molar mass which means more electrons, which means greater dispersion forces holding molecules together. Higher intermolecular forces leads to higher boiling points.