Question

oxygen is acting as an oxidizing agent in all of the following reactions excepta.\\( 2 c(s) + o_2(g) \
ightarrow 2 co(g)\\)b.\\( s(s) + o_2(g) \
ightarrow so_2(g)\\)c.\\( 2 f_2(g) + o_2(g) \
ightarrow 2 of_2(g)\\)d.\\( 2 na(s) + o_2(g) \
ightarrow na_2o_2(s)\\)e.\\( 2 mg(s) + o_2(g) \
ightarrow 2 mgo(s)\\)

Explanation:

To determine when oxygen is not an oxidizing agent, we check the oxidation state of oxygen. An oxidizing agent is reduced (decrease in oxidation state). In most reactions, O has an oxidation state of -2 (or -1 in peroxides). In reaction C: \(2 \text{F}_2(\text{g}) + \text{O}_2(\text{g})
ightarrow 2 \text{OF}_2(\text{g})\), F is more electronegative than O, so O has a +2 oxidation state here. This means O is oxidized (oxidation state increases from 0 to +2), so it acts as a reducing agent, not an oxidizing agent. In other reactions (A, B, D, E), O's oxidation state decreases (e.g., A: O from 0 to -2 in CO; B: O from 0 to -2 in \(SO_2\); D: O from 0 to -1 in \(Na_2O_2\); E: O from 0 to -2 in MgO), so O is an oxidizing agent there.

Answer:

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