Is there a highest temperature at which ice can exist? If so, what is it ? If not, why not?
a. Yes (0.01°); because the solid - gas phase boundary has a negative slope down to the triple point and the solid - liquid phase boundary has a positive slope up to the triple point, ice does not exist for temperatures greater than the triple point.
b. No; ice can exist at any temperature as long as the pressure is below the critical point.
c. Yes (0.01°); because the solid - liquid phase boundary has a negative slope down to the triple point and the solid - gas phase boundary has a positive slope up to the triple point, ice does not exist for temperatures greater than the triple point.
d. No; ice can exist at any temperature as long as the pressure is below the triple point.