Question

Hard water contains calcium and magnesium, which undergo oxidation and

clog water pipes. Which statement best describes this change as a chemical change?

Calcium and magnesium dissolve in water.


Calcium and magnesium evaporate on contact with the walls of the pipe.


Calcium and magnesium form precipitates of their respective oxides.

Answer 1

its CALCIUM AND MAGNESIUM FORM PRECIPITATES OF THEIR RESPECTIVE OXIDES
but that statement doesn't seem right as the percipitate formed by hard water is usually metal carbonates and hydrogen carbonates not oxides

hope that helps