Which type of substance can conduct electricity in the liquid phase but not in the solid phase?
metallic element
molecular compound
nonmetallic element
ionic compound

The answer here is ionic compound, because they dissociate in water to form ions that conduct electricity well through the solution.

Molecular compounds and nonmetallic elements tend to be poorer conductors, while metallic elements are good conductors in the solid phase.

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.