Question

Water and dichloromethane are insoluble in each other. When each is added to a test tube, two layers form. Which layer is water, and which is dichloromethane?

Short answer

Answer: In a test tube containing both water and dichloromethane, the bottom layer is dichloromethane and the top layer is water.

Step-by-step solution

Determine the densities of water and dichloromethane.

Look up the density values for water and dichloromethane. Water has a density of 1.00 g/mL, while dichloromethane has a density of 1.33 g/mL.

Compare the densities.

Since the density of dichloromethane (1.33 g/mL) is greater than the density of water (1.00 g/mL), dichloromethane is denser than water.

Identify the layer positions.

In a test tube, the denser substance will settle at the bottom while the less dense substance will be at the top, forming separate layers. In this case, the bottom layer will be dichloromethane (denser) and the top layer will be water (less dense). Conclusion: In a test tube containing both water and dichloromethane, the bottom layer is dichloromethane and the top layer is water.