[Jay-qu]

hallenrm said:

How, please explain, suppose some oxygen is produced at one electrode by the electrolysis of water, do you mean to say that this electrochemical process will be reversed tp produce water at that electrode.

yes that is what i suppose, and it was pure thought that brought me to the conclusion, I beleive the experiment would prove this.

[Turtle]

Jay-qu said:

yes that is what i suppose, and it was pure thought that brought me to the conclusion, I beleive the experiment would prove this.

I expect that each electrode produces both Oxygen & Hydrogen, that it doesn't recombine, & that the gases fill the tubes displacing all the electrolyte in them after some period of time.

I have the necessary apparatus & plan to conduct the experiment in the next few days.

hallenrm said:

This experiment can also work with carbon rods salvaged from a used drycell.

Any conductor is sufficient. Do you mean that carbon doesn't electrolyze?

[hallenrm]

Turtle said:

Any conductor is sufficient. Do you mean that carbon doesn't electrolyze?

Well we have used carbon rods extracted from torch-light carbon zinc drycells for many electrochemical experiment (as a replacement of platinum electrodes).!!

[Jay-qu]

It just makes sure that the electrode doesnt take place in the reaction. Now I remember a mythbuster episode, where they tried to break out of a jail cell, they where both trying to use electrolysis to oxidise the metal bars and break out. One of them was using AC while the other DC, after a few days of trying the DC had actually reduced the diameter of the bar while the AC didnt do a thing except boil the salsa they where using as an oxidant..

[Turtle]

Jay-qu said:

It just makes sure that the electrode doesnt take place in the reaction. Now I remember a mythbuster episode, where they tried to break out of a jail cell, they where both trying to use electrolysis to oxidise the metal bars and break out. One of them was using AC while the other DC, after a few days of trying the DC had actually reduced the diameter of the bar while the AC didnt do a thing except boil the salsa they where using as an oxidant..

I have clarification to offer & to request.
1) Those mythbuster chuckleheads couldn't think their ways out of wet paper sacks.
2) Carbon rod electrodes do indeed electrolyze.

yarchive.net said:

This reduces carbon
erosion, electrolytic reducion of hypochlorite (an intermediate in the
formation of chlorates) and helps control the pH. I use carbon rods,
and a 4A power supply.

http://yarchive.net/...hlorate_mk.html
3) The above link mentions platinum electrodes as did Charlie, albeit platinum plated titanium.
4) JayQ question: Given that the carbon electrodes do erode, do you have a chemical formulaic method to show the erodes carbon does not contribute to the reaction?
5) I plan to try the experiment tomorrow & make a video. I have no dry cell batteries, no platinum, no gold. I have copper, silver, lead, & steel.
6) Ball's in your courts.

[Jay-qu]

Yes, carbon does take place, but not all the time. It is used sometimes to avoid a reaction taking place. In the production of aluminium from alumina carbon electrodes are used and they react with the oxygen released when pure Aluminium is extracted from the oxide.

Some reaction could take place due to heating of reactants.. The mythbusters example was not intended to be a credible experiment, but it is what got me thinking that AC electolysis could not work. Maybe they where doing it wrong awaiting your experiment results

[Turtle]

Jay-qu said:

Some reaction could take place due to heating of reactants.. The mythbusters example was not intended to be a credible experiment, but it is what got me thinking that AC electolysis could not work. Maybe they where doing it wrong awaiting your experiment results

Everything they do is wrong! Twits & goobers those two. I wouldn't let them take a splinter out of a diseased rat's neck!
I'm off to prepare electrodes. I plan to coat the copper leads with acrylic where they connect to the electrodes of the other metals to isolate any reaction to a single metal. To the Lab! + +=

[Turtle]

Oky doky; the experiment is starting. I have a plastic tub with 2.5 gallons of tap water. With my multimeter set to measure resistance on the XK scale and the probes 6" apart, I measured 10,000 Ohms. I then stirred in 1 tablespoon of sodium chloride (kosher salt) and measured the resistance at 2,600 Ohms.
My transformer is rated at 20 VAC at the accessory terminals, but I measured 19 VAC on the multimeter. I have prepared copper electrodes & zinc-plated steel.
Photos & results to follow soon.

[Turtle]

Aha! After 10 minutes with the 19 Volt Alternating Current, the zinc-plated electrodes (screws) have collected a coating of myriad tiny bubbles. Given the low voltage & volume of electrolyte in the collecting vessels (drinking glasses) I will need to leave it running a while in order to collect an appreciable amount of gasses.

Unfortunatlely my camera cannot rersolve the tiny bubbles, but I'll work to get the best possible photos with what I have. More results to follow in a couple of hours.

[Turtle]

I have yet to measure the electrolyte temperature; data to follow.
The volume of the receiving vessels over each electrode is 9 fluid ounces.
First photos now in. Click on an image for a larger view.

[Turtle]

Electrolyte temperature is 76° F.
The gasses have started to collect in the top of the receiving vessels.
In the classic DC current version of this experiment, one vessel fills with Hydrogen while the other fills with Oxygen. Once full, a lighted splint is introduced into each vessel with the Hydrogen vessel expelling a vigorous flash of flame & popping sound while the lighted splint introduced into the Oxgen vessel increase in brightness & flame size.
I plan to continue the AC electrolysis untill I evacuate the vessels entirely & then introduce a lighted splint. What will the reaction be? How will it differ from the DC experiment results?

[Turtle]

It is now 3 hours of electrolyzing & I have collected about 1/2 teaspoon of gases in each vessel.

Pop Quiz! Take out your #2's.
Question #1) At the current rate of displacement in the vessels, how long will it take to completely evacuate them? hint
Question #2) Given the information already provided, what is the current amperage in this experiment? hint

[Jay-qu]

Drinking glasses approx 250mL, 1/2 teaspoon = 2.5 ml so you have to do 100 times the 3 hours you have been running = 300 hours

V = IR
20 = I(2600)
I = 7.69mA

Excellent work turtle! I propose the experiment be repeated with DC for comparison, what I expect is that the reaction taking place is the same BUT for the DC will be a lot faster. Possibly due to AC current not perfectly lining when it changes direction so that all the atoms that just got oxidised wont be reduced. Hence there would be a mixture of gases at the electrodes for the AC.

[Mercedes Benzene]

Turtle? Where DO you find time for such interesting experiments?

[Turtle]

Jay-qu said:

Excellent work turtle! I propose the experiment be repeated with DC...

Egracious. The DC experiment I have done before, so it is worth doing. However, this AC experiment I have never done & I find it quite interesting. I won't grade your test until I give more time for other responses. (plenty of time to check your work subtly;) )

Mercedes Benzene said:

Turtle? Where DO you find time for such interesting experiments?

I'm a recluse. Care to submit your quiz answers?

Speaking of pressure, what about the pressure of the gasses in the vessels?