Questions: Identify the oxidation-reduction reactions among the following: 1. Zn(s) + Cu^2+(aq) -> Zn^2+(aq) + Cu(s) 2. 2 Na(s) + Cl2(aq) -> 2 NaCl(s) 3. 2 Mg(s) + O2(g) -> 2 MgO All of 1,2 , and 3 1 and 2 only 2 and 3 only None of 1, 2, and 3 1 and 3 only

Solution Steps

In the reaction: \[ \mathrm{Zn}(\mathrm{s}) + \mathrm{Cu}^{2+}(\mathrm{aq}) \rightarrow \mathrm{Zn}^{2+}(\mathrm{aq}) + \mathrm{Cu}(\mathrm{s}) \]

• Zinc (\(\mathrm{Zn}\)) is oxidized from 0 to +2 oxidation state.
• Copper (\(\mathrm{Cu}^{2+}\)) is reduced from +2 to 0 oxidation state.

This is an oxidation-reduction (redox) reaction.

In the reaction: \[ 2 \mathrm{Na}(\mathrm{s}) + \mathrm{Cl}_{2}(\mathrm{aq}) \rightarrow 2 \mathrm{NaCl}(\mathrm{s}) \]

• Sodium (\(\mathrm{Na}\)) is oxidized from 0 to +1 oxidation state.
• Chlorine (\(\mathrm{Cl}_{2}\)) is reduced from 0 to -1 oxidation state.

This is an oxidation-reduction (redox) reaction.

In the reaction: \[ 2 \mathrm{Mg}(\mathrm{s}) + \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{MgO} \]

• Magnesium (\(\mathrm{Mg}\)) is oxidized from 0 to +2 oxidation state.
• Oxygen (\(\mathrm{O}_{2}\)) is reduced from 0 to -2 oxidation state.

This is an oxidation-reduction (redox) reaction.

Final Answer