What isotope has a mass of 79 and 44 neutrons?

bromine

Explanation:

The atomic mass of bromine (Br) is 79.90. There are two main isotopes at 79 and 81, which average out to the 79.90amu value. The 79 has 44 neutrons and the 81 has 46 neutrons. While it won't change the average atomic mass, scientists have made bromine isotopes with masses from 68 to 97.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.