The nozzle of a rocket is pointed downward so that, as fuel is ignited, the exhaust pushes downward. Why is this arrangement necessary for a rocket to function properly?

A. The rocket is protected from the heat of the exhaust

B. Burned fuel can be collected on the ground

C. As exhausted pushes down, the rocket is pushed up

D. This allows the rocket to be steered properly

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.