Which of the Following is the First, or Initiator, Reaction

Question

Which of the following is the first, or initiator, reaction in acid mine drainage and leaching?
A) oxidation of reduced sulfides to sulfate and the release of reduced iron (Fe²⁺)
B) rapid spontaneous reduction of oxidized iron (Fe³⁺)
C) rapid oxidation of sulfides to sulfate by oxidized iron (Fe³⁺)
D) microbial sulfate reduction

Accepted Answer

The first or initiator reaction in acid mine drainage and leaching involves the oxidation of reduced sulfides, such as pyrite (FeS2), to sulfate. This process releases reduced iron (Fe²⁺) into the environment, which can further react to exacerbate the production of acid mine drainage.