Answer
The heating curve of that process is represented by the drawing:
- The segment represented by "1" corresponds to the solid physical state, that occurs between -20 and 0$^{\circ}$ C.
Work Step by Step
You can use the Figure 3.8 (Page 81) as the basis to draw the heating curve.
Since the melting/freezing point of water is at $0^{\circ}$, at any value below that one, water will occur as a solid.