What phase of matter is NaOH?
Sodium hydroxide exists in the solid phase at room temperature, and can be found as as hemispherical white solid pellets:
If you heat sodium hydroxide to a temperature of 318 degrees Celsius, it will melt. If you continue to heat it, the NaOH liquid will become a gas (boil) at 1388 degrees Celsius.
If you place sodium hydroxide in water it dissolves, becoming an aqueous solution.