Question

oxygen is acting as an oxidizing agent in all of the following reactions except
a.
2 c(s) + o₂(g) → 2 co(g)
b.
s(s) + o₂(g) → so₂(g)
c.
2 f₂(g) + o₂(g) → 2 of₂(g)
d.
2 na(s) + o₂(g) → na₂o₂(s)
e.
2 mg(s) + o₂(g) → 2 mgo(s)

Explanation:

To determine when oxygen is not an oxidizing agent, we analyze the oxidation states:

• In an oxidizing agent, the element is reduced (oxidation state decreases).
• Option A: C (0) → CO (+2), O₂ (0) → CO (-2). O is reduced (oxidizing agent).
• Option B: S (0) → SO₂ (+4), O₂ (0) → SO₂ (-2). O is reduced (oxidizing agent).
• Option C: F₂ (0) → OF₂ (-1), O₂ (0) → OF₂ (+2). O is oxidized (not an oxidizing agent, it is a reducing agent here).
• Option D: Na (0) → Na₂O₂ (+1), O₂ (0) → Na₂O₂ (-1). O is reduced (oxidizing agent).
• Option E: Mg (0) → MgO (+2), O₂ (0) → MgO (-2). O is reduced (oxidizing agent).

Answer:

C. \( 2 \text{ F}_2(\text{g}) + \text{ O}_2(\text{g})
ightarrow 2 \text{ OF}_2(\text{g}) \)