A) The melting and boiling point of a compound depends on the elements, the bonds that form the molecule, and the geometry of the compound, so two compounds with a similar structure can have similar melting and boiling points.
Fluorethane has the molecular formula C2H5F, so poly(fluoroethane) may have a similar boiling point since its structure is similar.
B) This is because when a bond is formed, the chemical and physical properties of the compound change because there is a rearrangement of the electrons. So all the compounds that contain bromine will not have the same properties but it will depend on the elements with which they are linked and the type of link between them. If bromine bonds with an element with low electronegativity, such as a metal, for example, an ionic bond will be formed. This ionic bond with metal will give it different electrical properties and this compound can conduct electricity.