What is the Source of the Acidic PH of Some

Question

What is the source of the acidic pH of some mine runoff?
A) Iron ores are reduced by exposure to the atmosphere.
B) Pyrite is oxidized by exposure to the atmosphere and microbes.
C) Iron ores contain sulfuric acid (H₂SO₄).
D) Sulfur-containing ores are reduced by exposure to oxygen.
E) Hydrogen gas trapped in ore reacts with the atmosphere to produce hydrochloric acid (HCl).

Accepted Answer

Pyrite, also known as fool's gold, is a common mineral in many ores found in mines. When pyrite is exposed to oxygen and microbes, it oxidizes and produces sulfuric acid (H₂SO₄), which lowers the pH of the mine runoff. This process is known as acid mine drainage (AMD).