To determine which substance is reduced in the reaction [tex]\(2 Fe^{2+} + Cl_2 \rightarrow 2 Fe^{3+} + 2 Cl^-\)[/tex], we need to understand the concept of oxidation and reduction (redox reactions). In a redox reaction, oxidation refers to the loss of electrons, whereas reduction refers to the gain of electrons.
Let's break down the reaction step by step to analyze the changes in oxidation states of the reactants and products:
1. Identify the oxidation states:
- [tex]\(Fe^{2+}\)[/tex] has an oxidation state of +2.
- [tex]\(Fe^{3+}\)[/tex] has an oxidation state of +3.
- [tex]\(Cl_2\)[/tex] (molecular chlorine) has an oxidation state of 0.
- [tex]\(Cl^-\)[/tex] has an oxidation state of -1.
2. Determine the changes in oxidation states:
- [tex]\(Fe^{2+}\)[/tex] changes from +2 to +3.
- [tex]\(Cl_2\)[/tex] changes from 0 to -1.
3. Identify the substance being oxidized:
- [tex]\(Fe^{2+}\)[/tex] loses an electron to become [tex]\(Fe^{3+}\)[/tex]. This is oxidation:
[tex]\[
Fe^{2+} \rightarrow Fe^{3+} + e^-
\][/tex]
4. Identify the substance being reduced:
- [tex]\(Cl_2\)[/tex] gains electrons to become [tex]\(Cl^-\)[/tex]. This is reduction:
[tex]\[
Cl_2 + 2e^- \rightarrow 2 Cl^-
\][/tex]
Since reduction involves the gain of electrons, the substance that gains electrons is [tex]\(Cl_2\)[/tex].
Therefore, the substance that is reduced in the reaction [tex]\(2 Fe^{2+} + Cl_2 \rightarrow 2 Fe^{3+} + 2 Cl^-\)[/tex] is:
[tex]\[
\boxed{Cl_2, \text{ because it gained electrons}}
\][/tex]
