Hard water, which contains mg2+ and ca2+ ions, tends to form a ring in a bathtub due to its reaction with the soluble anions in soap. The formation of this insoluble material is an example of.

What is "the ring of fire"? a. a type of volcanic eruption b. an area around the pacific ocean c. a circle of volcanoes forming over a hot spot d. a region around a cinder cone in which ash is likely to land