When Does Water Completely Vaporize in a Constant Volume Process?

[Cozy_Powell]

Homework Statement

5 kg of a mixture of saturated liquid-vapor water is in a container of fixed volume 2,5 m³. Initially the temperature is 75 ºC and then the water is heated.
a) Find the temperature at which the water is completely vaporized.
b) Draw the temperature-specific volume diagram.

The Attempt at a Solution

a) Is easily solved from the tables and I've found a temperature of 140,7 ºC.

b) Here I am completely at a loss... From what I can understand from the problem, initially the process begins somewhere inside the "dome shaped" region.
The specific volume is constant and equals 0,5 m³/kg, which lies between Vf and Vg for 75ºC. I put a red dot where I think the process begins... is it right?
But now... how can we get to the final state? I think the final state is a saturated vapor state... is it right?
Because specific volume is constant, I put a blue dot where I think the final state is... but how can the temperature change inside the dome shaped region??

Many thanks!

 

[Cozy_Powell]

oh... I think I got it! Temperature changes because pressure is not constant... So the diagram should be a straight line from red to blue dot. Is this okay?