Problem: The table below shows the normal boiling points of benzene and benzene derivatives.Why is the boiling point of bromobenzene higher than that of chlorobenzene?

FREE Expert Solution

•  Chlorobenzene and bromobenzene both exhibit two types of intermolecular forces of attraction (IMFA)

1. London Dispersion Forces (LDF): This is present in all molecules and is the main force exhibited by non- polar molecules. The benzene ring of chlorobenzene and bromobenzene exhibits this type of IMFA.

2. Dipole-dipole Forces (DDF): This is exhibited by molecules which have a net dipole caused by the presence of an electronegative atom. The halogens (Cl and Br) are responsible for this type of IMFA in the benzene derivatives.

View Complete Written Solution
Problem Details
The table below shows the normal boiling points of benzene and benzene derivatives.

C6H6, benzene, is a six membered ring with alternating single and double bonds and a normal boiling point of 80 degrees celsius.  C6H5Cl, chlorobenzene, is a benzene ring with a chlorine atom attached to one of the carbons instead of a hydrogen and a normal boiling point of 132 degrees celsius.  C6H5Br, bromobenzene, is a benzene ring with a bromine atom attached to one of the carbons instead of a hydrogen atom and a normal boiling point of 156 degrees celsius.  C6H5OH, called phenol or hydroxybenzene, is a benzene ring with an OH attached to one of the carbons instead of a hydrogen and a normal boiling point of 182 degrees celsius.

Why is the boiling point of bromobenzene higher than that of chlorobenzene?