Chapter 24, Problem 24.22P

Interpretation Introduction

Interpretation:

From the following oxidation-reduction reaction from problem $24-20$ the species that are oxidized, reduced and the oxidizing agent and the reducing agents have to be determined.

$\begin{array}{l}\left(a\right)6F{e}^{2+}\left(aq\right)+14H^{+}\left(aq\right)+C{r}_2{O}_7^{2-}\left(aq\right)\to 6F{e}^{3+}\left(aq\right)+2C{r}^{3+}\left(aq\right)+7H_{2}O\left(l\right)\\ \\ \left(c\right)C{H}_4\left(g\right)+2O_2\left(g\right)\to C{O}_2\left(g\right)+2H_{2}O\left(g\right)\\ \\ \left(e\right)C{l}_2\left(g\right)+NaBr\left(aq\right)\to B{r}_2\left(l\right)+NaCl\left(aq\right)\end{array}$

Concept introduction:

In an oxidation-reduction reaction electrons will be transferred from one reactant to another reactant.  Hence the oxidation-reduction reactions are also called electron transfer reactions.

The reactant is called the oxidizing agent if it accepts electrons and the reactant is called the reducing agent if it donates electrons.

Normally a specific atom in the oxidizing agent accepts the electrons so its oxidation state decreases.  Similarly, a specific atom in the reducing agent donates the electrons, so its oxidation state increases.  Therefore the oxidizing agent contains atoms that are reduced, and the reducing agent contains atoms that are oxidized.