Are oil and liquid ammonia considered to be miscible?

The belief that ammonia is heavier than oil suggests a misunderstanding of the miscibility of oil and liquid ammonia. The key concept here is that miscibility refers to the capacity of two substances to mix together to form a homogeneous solution.

Liquid ammonia and oil are not miscible. They do not mix uniformly despite their respective densities. Ammonia is a polar molecule, while oil is typically composed of non-polar hydrocarbons, causing them to repel each other rather than form a solution. Thus, when mixed, they separate into distinct layers. This immiscibility is critical in applications that involve both substances, such as in refrigeration systems, where the separation of oil and ammonia can impact system performance and efficiency.

The correct understanding is centered around the interaction of their chemical properties rather than their densities or weights. This distinction is important for anyone training in industrial ammonia refrigeration.