If a propane tank is used to store anhydrous ammonia, what color does the brass nozzle turn?

The correct answer is blue, which indicates that the brass nozzle has undergone a chemical change due to contact with anhydrous ammonia. Anhydrous ammonia is a colorless gas that can cause corrosion to metals, particularly brass, which is often used in fittings and nozzles. When brass is exposed to anhydrous ammonia, it tends to develop a blue discoloration as a result of the chemical reaction between the ammonia and the copper content in the brass alloy. This blue color is significant as it serves as a visual indicator of potentially harmful corrosion and aids in identifying equipment that may have been improperly used or is at risk of failure.

This understanding is critical for ensuring safety in handling and storage, as it reflects the importance of using appropriate materials in environments where anhydrous ammonia is present. Recognizing these signs can help prevent accidents and ensure compliance with safety regulations.