Sunday, July 11, 2010

Chemistry Form Four : Chapter 6 - Electrolysis of copper (II) sulphate

Electrolysis of copper (II) sulphate using carbon electrode. The bulb is lighted indicates that copper (II) sulphate is an electrolyte which can conduct electricity. Carbon electrode is inert which does not react with electrolyte or product of electrolysis.

  At anode : Hydroxide ions ions are selectively
  discharged. Gas bubbles are formed which lighted up a glowing wooden splinter. This gas is oxygen.

At cathode : Copper ions are selectively discharged. Shiny brown metal deposited around cathode. This metal is copper.


Electrolysis copper (II) sulphate solution with copper electrodes
At cathode : Copper ions are selectively discharged. Shiny brown metal deposited, makes the cathode thicker. This metal is copper.
At anode : Copper electrode eroded and became thinner. Copper anode dissolved to form copper ions.


Anonymous said...

Samuel Khor:
During the first experiment that is using carbon electrolyte:
1)The Copper metal discharged is an atom or an ion?
2)Why doesn't the blue colour of CuSO4 becomes lighter?

Cikgu Wong said...

Dear Samuel Khor,

Ouestion No. 1:The copper ions are selectively discharged at cathode to become copper metal. Therefore, it is an atom.

Question No.2: It is because I did this experiment in a short time. If you do a bit longer, the intensity of blue colour will fade.

Samuel said...

Oh I see, thank you...

Iam Iyzk said...

What about copper11sulphate using platinum electrodes

cikgu wong said...

you will get same result as you use carbon as electrodes. Platinum and carbon are inert electrodes which do not react with other substances during electrolysis process.

Michelle Do said...

for the copper electrodes could you please provide the overall net equation and the two oxidation/reduction half equations?

Michelle Do said...

during the electrolysis for the copper electrodes did you find that there was black specks on the anode? when i did the experiment the anode didnot get that normal?

BTW could you please provide half equations for the copper electrode experiment, thank you