You are given a glass rod that is negatively charged and a pinwheel that has a negative charge. What will happen when the glass rod is brought close to the pinwheel? Why?

they will repel each other

Explanation:

When these two are brought close to one another they will repel each other. This is similar to what happens with magnets, when two objects share the same polarity one object will create a repulsive force upon the second object and push it away. This repellent force is caused by an electric field from the same charged electrons in the atoms of the object. Since in this case both the glass rod and the pinwheel have a negative charge they will repel each other when they come into proximity of one another.

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.