An atom has (+2) charge, if it has 12 electrons, what is its atomic number?

14.

Explanation:

Electrons have a negative charge, and since the atom has a charge of (+2) it would mean there are 14 protons. (2 more than the amount of electrons, to create a positive charge).

Protons also determine the Atomic number so, the atomic number is 14.

Amount of protons = atomic number.

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.

the objects have the same charge.