In order to determine which half-reaction correctly describes the oxidation process in the given redox reaction:
[tex]\[ Zn \,(s) + 2 HCl\,(aq) \rightarrow ZnCl_2\,(aq) + H_2\,(g) \][/tex]
we need to identify the component that loses electrons (undergoes oxidation).
Oxidation is defined as the loss of electrons. We will examine each option given and determine whether it represents oxidation or reduction.
1. [tex]\[ Zn^{2+}\,(s) + 2e^{-}\,(aq) \rightarrow Zn\,(s) \][/tex]
- Here, zinc ions (\( Zn^{2+} \)) gain electrons to form neutral zinc metal (\( Zn \)). This is a reduction process, not oxidation.
2. [tex]\[ Zn\,(s) \rightarrow Zn^{2+}\,(aq) + 2e^{-} \][/tex]
- In this half-reaction, zinc metal (\( Zn \)) loses two electrons to form zinc ions (\( Zn^{2+} \)). This is indeed an oxidation process because electrons are lost.
3. [tex]\[ 2H^{+} + 2e^{-} \rightarrow H_2 \][/tex]
- In this half-reaction, protons (\( H^{+} \)) gain electrons to form hydrogen gas (\( H_2 \)). This describes a reduction process rather than oxidation.
4. [tex]\[ H_2 + 2e^{-} \rightarrow 2H^{+} \][/tex]
- In this half-reaction, hydrogen gas (\( H_2 \)) would lose electrons to form protons (\( H^{+} \)). This represents an oxidation process. However, it pertains to hydrogen and not zinc.
Given the half-reactions and focusing on the species involved in the provided redox reaction involving zinc, the correct answer is:
[tex]\[ Zn\,(s) \rightarrow Zn^{2+}\,(aq) + 2e^{-} \][/tex]
So, the half-reaction that correctly describes the oxidation taking place is:
[tex]\[ \boxed{Zn\,(s) \longrightarrow Zn^{2+}\,(aq) + 2e^{-}} \][/tex]
