Write a complete chemical formula, including physical state symbol, for each element listed below in its standard state. The first row of the table has been completed for you. element formula
iron Fe(s)
plutonium
lodine
helium

Explanation:

Plutonium

The symbol is Pu and it exists in the solid state.

The complete chemical formular is given as; Pu(s)

Iodine

The symbol is I and it exists exists as a lustrous, purple-black non-metallic solid at standard conditions

The complete chemical formular is given as; I(s)

Helium

The symbol is He and it exists in the gaseous state.

Te complete chemical formular is given as; He(g)

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.