At 70 degrees Fahrenheit, if R11, water, and lubricating oil are mixed in a container, in what order will they settle from top to bottom?

To understand the settling order of the fluids when R11, water, and lubricating oil are mixed, it's important to consider the densities of each substance.

Water has a density of about 1 g/cm³, which is higher than that of most oils, which typically have densities around 0.8-0.9 g/cm³. R11, a refrigerant, generally has a density of approximately 1.5 g/cm³, which is higher than both water and oil.

When these substances are combined in a container, the fluid with the highest density will settle at the bottom while the fluid with the lowest density will float to the top. Therefore, the correct order from top to bottom would be oil, which is the least dense, followed by water, and then R11 at the bottom, as it is the most dense of the three substances.

This explanation clearly shows that choice C accurately reflects the behavior of these fluids based on their respective densities, leading to the conclusion that oil will settle at the very top, followed by water, and R11 resting at the bottom.