Investigate: Note the empty jars on the shelf that can be filled by using the slider. Set the amount to 2.000 moles of carbon (mol C), then press Start. Each jar holds exactly one mole of carbon. Your goal is to determine the mass in grams of two moles of carbon. Before you can find the mass, what do you need to know?

Turn on Show molar mass. What is the molar mass of carbon?

What do you think the mass of 2.000 moles of carbon will be?

Drag the jars to the balance. What is the mass of 2.000 moles of C?

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.