Sciencemadness Discussion Board

Electrolysis of copper chloride

Doktor Klawonn - 22-4-2011 at 14:15

Introduction

Electrolysis of copper (II) chloride is a basic experiment in school chemistry. The products are easy to show and the sum equation of the reaction is simple.

Chemicals and apparatus

- U tube
- carbon electrodes
- copper (II) chloride
- sodium iodide
- destilled water
- stand
- wire
- electric power supply

Warning

In this experiment, chlorine gas may escape.

Experimental

Copper (II) chloride is dissolved in destilled water.[1] The resulting solution is filled into a U-tube to two thirds height.[2]

cucl1.JPG - 6kB cucl2.JPG - 5kB

Carbon electrodes are placed into the sides of the U-tube. The electrodes are connected to the power supply.

cucl3.JPG - 9kB

Chlorine gas is evolved at the anode. The gas turns a solution of sodium iodide brown.[3]

cucl4.JPG - 6kB cucl5.JPG - 5kB

Copper is deposited at the catode.

cucl6.JPG - 7kB

Sum reaction is:

CuCl<sub>2</sub> --> Cu + Cl<sub>2</sub>

Reaction of chlorine gas with sodium iodide solution:

Cl<sub>2</sub> + 2 NaI --> 2 NaCl + I<sub>2</sub>

Remarks

[1] The use of tap water may result in a turbid solution.
[2] This leaves room for the electrodes and for chlorine gas, which can then be collected from the anode.
[3] Other reactions to show the chlorine are possible.

Links

- This experiment in a video

jamit - 22-4-2011 at 16:05

what were you trying to do in this experiment? What would have happened if you continued the electrolysis until the very end when all the copper II chloride would be consumed? Would it produce copper II chlorate??


Doktor Klawonn - 24-4-2011 at 03:36

Quote: Originally posted by jamit  
what were you trying to do in this experiment?


This is a basic experiment in electrochemistry at school. The purpose is to understand concepts like ions and atoms or the effect of electric current on chemicals.

Quote: Originally posted by jamit  

What would have happened if you continued the electrolysis until the very end when all the copper II chloride would be consumed? Would it produce copper II chlorate??


The copper would deposit on the negative electrode (catode) and chlorine gas would be generated at the positive electrode (anode) untill the conductivity of the solution drops considerably to stop the electrolysis. There will be no chlorate produced.