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 state of oxygen in each reaction:

• Option A: In \( \ce{O2} \) (oxidation state = 0), in \( \ce{CO} \), O has -2. Oxygen gains electrons (reduction), so it's an oxidizing agent.
• Option B: In \( \ce{O2} \) (0), in \( \ce{SO2} \), O has -2. Oxygen is reduced, acting as an oxidizing agent.
• Option C: In \( \ce{O2} \) (0), in \( \ce{OF2} \), O has +2 (since F is -1, \( 2(-1) + x = 0 \Rightarrow x = +2 \)). Oxygen loses electrons (oxidation), so it acts as a reducing agent, not an oxidizing agent.
• Option D: In \( \ce{O2} \) (0), in \( \ce{Na2O2} \), O has -1. Oxygen is reduced, acting as an oxidizing agent.
• Option E: In \( \ce{O2} \) (0), in \( \ce{MgO} \), O has -2. Oxygen is reduced, acting as an oxidizing agent.

Answer:

C. \( \ce{2 F2(g) + O2(g) → 2 OF2(g)} \)