Nitric oxide, NO·, is a radical thought to cause ozone destruction by a mechanism similar to that of hydrofluorocarbons. One source of NO· in the stratosphere is supersonic aircraft whose jet engines convert small amounts of N2 and O2 to NO·. Write the propagation steps for the reaction of O3 with NO·.

O3 + NO. = O2. + NO2

2O. +NO2 = NO. + 2O2

Explanation:

NO. = Radical

O. & O2. = Radical

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.