Answer
a. Vapor
b. Solid
Work Step by Step
a. Figure 13–22, the phase diagram for water, shows that the point $(90^{\circ}C, 0.01 atm)$ is in the vapor region.
b. Figure 13–22, the phase diagram for water, shows that the point $(-20^{\circ}C, 0.01 atm)$ is in the solid region.
