At what temperature does anhydrous ammonia freeze?

Anhydrous ammonia, also known as ammonia without water, has a freezing point of approximately -107.9°F. This characteristic is crucial for industrial refrigeration applications, where ammonia is commonly used as a refrigerant due to its efficient heat transfer properties. Understanding the freezing point of ammonia is essential for operators to ensure that temperatures in refrigeration systems remain above this threshold, thus preventing solidification of ammonia that could disrupt the system's functionality.

The other choices reflect temperatures that do not align with the known freezing point of anhydrous ammonia and may cause confusion if operators are not aware of the exact figures. Being familiar with the specific temperature at which ammonia freezes is important for safety and for the proper operation of refrigeration systems utilizing this substance.