When oxidized, how do iron and manganese change the water's color?

When iron and manganese are oxidized in water, they typically undergo a chemical transformation that affects the water's appearance. Oxidation converts dissolved iron and manganese ions into their oxidized forms, which tend to precipitate out of solution as solids.

In the case of iron, when it is oxidized, it changes from ferrous iron (Fe²⁺), which is clear in solution, to ferric iron (Fe³⁺), which can form rust-colored particles. This process can lead to turbidity in the water, giving it a yellow-brown appearance.

Manganese behaves similarly; when manganese (Mn²⁺) is oxidized, it can form manganese dioxide (MnO₂), which appears as black particles. This creates a visual transition where the water can go from being relatively clear to displaying a combination of yellow and black hues due to the presence of these precipitated solids.

Thus, the transformation from clear water to a turbid mixture that combines yellow (from oxidized iron) and black (from oxidized manganese) is characteristic of the changes that occur when these elements are oxidized. This provides a clear rationale for why the correct choice reflects a turbid yellow to black coloration in the water upon oxidation.