Solid water (ice) is slowly warmed from a very low temperature.
(a) What minimum external pressure P1 must be applied to the solid if a melting phase transition is to be observed? Describe the sequence of phase transitions that occur if the applied pressure P is such that P < P1'
(b) Above a certain maximum pressure P2, no boiling transition is observed. What is this pressure? Describe the sequence of phase transitions that occur if P1 < P < P2'