What phase of matter is NaOH?
Sodium hydroxide exists in the solid phase at room temperature.
You would find it in the lab as hemispherical white solid pellets.
The phase of a substance depends on temperature and pressure.
As you heat a solid, it will melt and change to the liquid phase.
If you heat the liquid even more, the liquid will boil and change to the gas phase.
NaOH melts at 318 °C. It remains in the liquid phase until the temperature reaches 1388 °C.
At 1388 °C, NaOH boils. At temperatures above 1388 °C, NaOH exists in the gas phase.