Question

oxygen is acting as an oxidizing agent in all of the following reactions except

a. \\(2\text{ c(s)} + \text{o}_2\text{(g)} \
ightarrow 2\text{ co(g)}\\)

b. \\(\text{s(s)} + \text{o}_2\text{(g)} \
ightarrow \text{so}_2\text{(g)}\\)

c. \\(2\text{ f}_2\text{(g)} + \text{o}_2\text{(g)} \
ightarrow 2\text{ of}_2\text{(g)}\\)

d. \\(2\text{ na(s)} + \text{o}_2\text{(g)} \
ightarrow \text{na}_2\text{o}_2\text{(s)}\\)

e. \\(2\text{ mg(s)} + \text{o}_2\text{(g)} \
ightarrow 2\text{ mgo(s)}\\)

Explanation:

Define oxidizing agent and oxidation state of elemental oxygen

$$
LATEXBLOCK0
$$

Determine oxidation states of oxygen in the products

$$
LATEXBLOCK1
$$

Identify the exception where oxygen is not reduced

$$ \text{In reaction C, oxygen is oxidized (oxidation state increases from } 0 \text{ to } +2\text{), so it acts as a reducing agent, not an oxidizing agent.} $$

Answer:

• (A) \(2\text{ C(s)} + \text{O}_2\text{(g)}

ightarrow 2\text{ CO(g)}\)

• (B) \(\text{S(s)} + \text{O}_2\text{(g)}

ightarrow \text{SO}_2\text{(g)}\)</mcq-correct>

• **(C) \(2\text{ F}_2\text{(g)} + \text{O}_2\text{(g)}

ightarrow 2\text{ OF}_2\text{(g)}\) (Correct answer)**
<mcq-option>(D) \(2\text{ Na(s)} + \text{O}_2\text{(g)}
ightarrow \text{Na}_2\text{O}_2\text{(s)}\)

• (E) \(2\text{ Mg(s)} + \text{O}_2\text{(g)}

ightarrow 2\text{ MgO(s)}\)