Chapter 18, Problem 18.85QP

Interpretation Introduction

Interpretation:

An experiment has to be described to identify the cathode and anode in a galvanic cell consisting of copper and zinc electrode.

Concept Introduction:

Galvanic cell is an electrochemical device in which electrical energy is derived from a chemical reaction.  It has two half cells, oxidation half cell (anode) and reduction half cell (cathode).  The two half cells are connected by a salt bridge.

Redox reactions are the reactions in which both oxidation and reduction take place simultaneously.  Oxidation is the removal electron from an atom or ion.  Oxidation process increases the oxidation number.  Reduction is the addition of electron to an atom or ion.  Reduction process decreases the oxidation number.  The electrochemical reaction in a Daniel cell is an example of redox reaction.

${\text{Zn}}_{\left(\text{s}\right)}\text{+}{\text{CuSO}}_{\text{4}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{ZnSO}}_{\text{4}}\text{+}\text{Cu}$