Chapter 19, Problem 19.15QP

Interpretation Introduction

Interpretation:

Whether nitrate ion will oxidize ${\text{Mn}}^{\text{2+}}\text{to}{\text{MnO}}_{\text{4}}{}^{\text{-}}$ or not has to be checked.

Concept Introduction:

Half-reactions: A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction. Often, the concept of half-reactions is used to describe what occurs in an electrochemical cell, such as a Galvanic cell battery.

Electro chemical cells: The anode (negative) the electrode is at which the oxidation alf-reactions occurs and cathode (positive) is the electrode at which the reduction half-reactions occurs. Hence the galvanic cell converts chemical energy into electrical energy.

The half-cell reactions: The anode, where oxidation occurs, is $\text{Zn}\left(\text{s}\right){\text{= Zn}}^{\text{2+}}\left(\text{aq}\right)\text{ +}\left({\text{2e}}^{\text{-}}\right)$. The zinc loses two electrons to form ${\text{Zn}}^{\text{2+}}$. The half-reaction on the cathode where reduction occurs is ${\text{Cu}}^{\text{2+}}\left(\text{aq}\right){\text{+ 2e}}^{\text{-}}\text{= Cu}\left(\text{s}\right)$. Here, the copper ions gain electrons and become solid copper.