Though you add heat, the temperature of boiling water remains constant because ...water has a constant boiling temperature.it takes energy to break covalent bonds.it takes energy to break hydrogen bonds.it takes energy to circulate water.None of the above. The temperature rises during boiling.
CREASON: Correct! At boiling, all the added heat is used to break hydrogen bonds. Free of the water mass, the departing steam carries away all the added energy, with none left over to raise the temperature.