To determine which reaction correctly describes the oxidation that is taking place, we first need to review the definitions of oxidation and reduction:
- Oxidation is the loss of electrons.
- Reduction is the gain of electrons.
Given the overall redox reaction:
[tex]\[ Zn (s) + 2 HCl (aq) \longrightarrow ZnCl_2 (aq) + H_2 (g) \][/tex]
We need to consider the possible half-reactions provided and identify which one corresponds to oxidation. Let's examine each option:
1. Reaction 1:
[tex]\[ Zn^{2+} (s) + 2e^{-} (aq) \longrightarrow Zn (s) \][/tex]
In this reaction, [tex]\( Zn^{2+} \)[/tex] is gaining electrons to form [tex]\( Zn \)[/tex]. Since gaining electrons is the process of reduction, this reaction describes a reduction half-reaction, not oxidation.
2. Reaction 2:
[tex]\[ Zn (s) \longrightarrow Zn^{2+} (aq) + 2e^{-} \][/tex]
In this reaction, [tex]\( Zn \)[/tex] is losing electrons to form [tex]\( Zn^{2+} \)[/tex]. Since losing electrons is the process of oxidation, this reaction describes an oxidation half-reaction.
3. Reaction 3:
[tex]\[ 2H^{+} + 2e^{-} \longrightarrow H_2 (g) \][/tex]
In this reaction, [tex]\( H^{+} \)[/tex] ions are gaining electrons to form [tex]\( H_2 \)[/tex]. This is the process of reduction since electrons are being gained, not lost.
Based on these observations, the reaction that correctly describes the oxidation process is:
[tex]\[ Zn (s) \longrightarrow Zn^{2+} (aq) + 2e^{-} \][/tex]
Therefore, the correct answer is:
[tex]\[ 2 \][/tex]
This reaction involves the oxidation of [tex]\( Zn \)[/tex] as it loses electrons to form [tex]\( Zn^{2+} \)[/tex].
