Rachel and Billy are conducting an experiment. The mass of their candle before burning was 7.0 grams. After burning the candle for six minutes, the mass went down to 5.5 grams. What can the students determine about the results of their experiment? A. The law of conservation of mass cannot be applied over short periods of time. B. The law of conservation of mass does not apply to chemical changes like burning. C. The law of conservation of mass was broken because the mass of the candle decreased. D. The law of conservation of mass was not broken because the missing mass was released as smoke

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.