Groundwater often has low levels of dissolved oxygen because it is not continually exposed to the atmosphere. When groundwater reaches the surface, the following reaction involving soluble iron(II) can occur. What are the oxidation numbers of the elements in the product, Fe(OH) ₃?
4Fe²⁺(aq) + O₂(g) + 2H₂O(l) $\rightarrow$ 8OH^- $\rightarrow$ Fe(OH) ₃(s)

Question

Groundwater often has low levels of dissolved oxygen because it is not continually exposed to the atmosphere. When groundwater reaches the surface, the following reaction involving soluble iron(II) can occur. What are the oxidation numbers of the elements in the product, Fe(OH) ₃?
4Fe²⁺(aq) + O₂(g) + 2H₂O(l)

\rightarrow

8OH^-

\rightarrow

Fe(OH) ₃(s)

Quizplus · Accepted Answer

In the reaction, FeS has iron in the +2 oxidation state and sulfur in the -2 oxidation state. In the product Fe(OH)S, the oxidation state of oxygen is -2, the oxidation state of hydrogen is +1, and the sum of the oxidation states of Fe, O, and H must equal the charge of the ion (-1). Solving for Fe, we get +3 as the oxidation state. Therefore, the correct choice is E, where Fe = +3, O = -2, and H = +1.

Groundwater Often Has Low Levels of Dissolved Oxygen Because It →\rightarrow→

Groundwater Often Has Low Levels of Dissolved Oxygen Because It $\rightarrow$