A solid substance has a molar volume which is smaller than that of its liquid phase. Which of the following statements regarding the solid-liquid phase transition is/are true?
(More than one answer may be selected).
A The slope of the solid-liquid phase boundary line is directly proportional to the temperature at which the phases are in equilibrium.
B The magnitude of the slope of the solid-liquid phase-boundary line will be much greater than that of the liquid-vapour phase boundary line.
C The fusion (melting) process is always exothermic.
D The slope of the solid-liquid phase boundary is positive.