Question

are covalent bonds broken when....

melt benzene

melt quartz

boiling C2H5OH

evaporating water

disolving bromine in water?

Answer 1

You really need to define what you mean by covalent bond in order for us to answer this question. For example, hydrogen bonds are broken when C2H5OH is boiled but H bonds are only about 1/20 as strong as a regular covalent bond. Same thing for crystal structure. Are the bonds in the crystal structure of solid benzene covalent bonds by your definition.