Which one is the positive?

J

Joe McElvenney

Guest
Hi,

There is a question a little way up the group about a power
connector and which of the leads is positive/negative. Now
supposing you had the same problem with only the contents of the
average kitchen cupboard to hand, how would one go about
determining polarity?

I seem to remember from my school science classes of many
years ago, such things as gases bubbling off the end of wires
immersed in slightly acid solutions (vinegar and water) or maybe
electro-what's-it (as used in DNA matching) employing possibly
toilet paper and some easily to hand substance.

Any ideas ??


Cheers - Joe
 
"Joe McElvenney" <ximac@btinternet.com> wrote in message
news:VA.00000070.003d52bb@btinternet.com...
Hi,

There is a question a little way up the group about a power
connector and which of the leads is positive/negative. Now
supposing you had the same problem with only the contents of the
average kitchen cupboard to hand, how would one go about
determining polarity?

I seem to remember from my school science classes of many
years ago, such things as gases bubbling off the end of wires
immersed in slightly acid solutions (vinegar and water) or maybe
electro-what's-it (as used in DNA matching) employing possibly
toilet paper and some easily to hand substance.

Any ideas ??


Cheers - Joe


I hear you but there are so many 'cheapo' digital meters around now that
Click to expand...
IMHO everyone should have one in the cupboard, much easier than making
solutions and handy for lots of situations.

--
Regards ..... Rheilly Phoull
 
On Wed, 22 Dec 2004 20:15:04 +0800, "Rheilly Phoull"
<Rheilly@bigpong.com> wrote:


I hear you but there are so many 'cheapo' digital meters around now that
IMHO everyone should have one in the cupboard, much easier than making
solutions
Click to expand...
....

Yes; it helps to find them! ;)

--
John Fields
 
On Wed, 22 Dec 2004 12:10:40 -0500, John Popelish <jpopelish@rica.net>
wrote:


The positive electrode will release oxygen an the negative will
release hydrogen. There will be twice as much hydrogen as oxygen.
More bubbles = negative.
Click to expand...
---
Yeah, I know, but I didn't see anything linking the quantity of gases
evolved with the polarity of the electrodes. Maybe I missed it...

--
John Fields
 
Dumb question time. If you ran AC for the electrolysis, would you get
separated H and O in each glass? (one gas on each half cycle) Could be
'explosive'.
GG
 
stratus46@yahoo.com wrote:
Dumb question time. If you ran AC for the electrolysis, would you get
separated H and O in each glass? (one gas on each half cycle)
Click to expand...

You get mixed H2 and O2.

Could be 'explosive'.
Click to expand...
Very! Google [brown's gas].


--
John Popelish
 
<stratus46@yahoo.com> wrote in message
news:1103965038.838545.57910@f14g2000cwb.googlegroups.com...
Dumb question time. If you ran AC for the electrolysis, would you get
separated H and O in each glass? (one gas on each half cycle) Could be
'explosive'.
GG
Click to expand...
It's possible that whatever gas gets formed during one half cycle is
reabsorbed during the other half cycle. But that's just a WAG.

Just take the gas separation stuff - inverted test tubes or whatever -
off and let the gasses mix together in the same glass. That way, you
can use DC.
 
What a rat's nest. The first link after googling on "brown's gas"

http://www.phact.org/e/bgas.htm

Robert

"John Popelish" <jpopelish@rica.net> wrote in message
news:41CDA6CE.4062F199@rica.net...
stratus46@yahoo.com wrote:

Dumb question time. If you ran AC for the electrolysis, would you get
separated H and O in each glass? (one gas on each half cycle)


You get mixed H2 and O2.

Could be 'explosive'.

Very! Google [brown's gas].


--
John Popelish
Click to expand...
 
Robert wrote:

"John Popelish" <jpopelish@rica.net> wrote in message
news:41CDA6CE.4062F199@rica.net...
(snip)
Google [brown's gas].

What a rat's nest. The first link after googling on "brown's gas"

http://www.phact.org/e/bgas.htm
Click to expand...
Yea. Isn't it amazing that electrically breaking water into its
component elements can make so many people lose their minds?

--
John Popelish
 
What a rat's nest. The first link after googling on "brown's gas"

http://www.phact.org/e/bgas.htm

Yea. Isn't it amazing that electrically breaking water into its
component elements can make so many people lose their minds?
John Popelish
Click to expand...
I can't understand the claim of producing monatomic H and storing it. I
thought that it would combine to diatomic H2 at room temperature on it's
own.

Robert
 
Joe McElvenney wrote:
Hi,

There is a question a little way up the group about a power
connector and which of the leads is positive/negative. Now
supposing you had the same problem with only the contents of the
average kitchen cupboard to hand, how would one go about
determining polarity?

I seem to remember from my school science classes of many
years ago, such things as gases bubbling off the end of wires
immersed in slightly acid solutions (vinegar and water) or maybe
electro-what's-it (as used in DNA matching) employing possibly
toilet paper and some easily to hand substance.

Any ideas ??


Cheers - Joe
Click to expand...
http://www.nmsea.org/Curriculum/7_12/electrolysis/electrolysis.htm
--
John Popelish
 
On Wed, 22 Dec 2004 10:48:33 GMT, Joe McElvenney
<ximac@btinternet.com> wrote:

Hi,

There is a question a little way up the group about a power
connector and which of the leads is positive/negative. Now
supposing you had the same problem with only the contents of the
average kitchen cupboard to hand, how would one go about
determining polarity?

I seem to remember from my school science classes of many
years ago, such things as gases bubbling off the end of wires
immersed in slightly acid solutions (vinegar and water) or maybe
electro-what's-it (as used in DNA matching) employing possibly
toilet paper and some easily to hand substance.
Click to expand...
---
John Popelish's link was good, but I didn't see any way to determine
whether the positive or negative wire was evolving hydrogen. Try
this:

1. Get a large, electrically non-conductive container (Teflon coated
pot, ceramic casserole dish, or something like that) and fill it
with tap water.

2. Submerge two small glasses in the pot so that they fill up with
water, then turn them over underwater so that their rims are
touching the bottom of the container and they're still full of
water.

3. Get two pieces of wire long enough to reach from the bottom of the
pot to your power supply connector.

4. Strip one end of both wires and slip the stripped ends under the
rims of the glasses without letting any air get into the glasses.
One wire per glass, and make sure the stripped ends don't stick out
from under the glasses.

5. Strip the other ends and connect them to your power supply.
Gas bubbles should begin forming on the stripped ends of the wires
under the glasses.

6. Let everything keep going until enough gas has collected in the
glasses so that you can clearly see that one glass has twice as
much gas in it as the other. The wire under that glass (the one
with twice as moch gas in it) will be connected to the negative
terminal of your power supply.


--
John Fields
 
John Fields wrote:
On Wed, 22 Dec 2004 10:48:33 GMT, Joe McElvenney
ximac@btinternet.com> wrote:

Hi,

There is a question a little way up the group about a power
connector and which of the leads is positive/negative. Now
supposing you had the same problem with only the contents of the
average kitchen cupboard to hand, how would one go about
determining polarity?

I seem to remember from my school science classes of many
years ago, such things as gases bubbling off the end of wires
immersed in slightly acid solutions (vinegar and water) or maybe
electro-what's-it (as used in DNA matching) employing possibly
toilet paper and some easily to hand substance.

---
John Popelish's link was good, but I didn't see any way to determine
whether the positive or negative wire was evolving hydrogen. Try
this:

1. Get a large, electrically non-conductive container (Teflon coated
pot, ceramic casserole dish, or something like that) and fill it
with tap water.

2. Submerge two small glasses in the pot so that they fill up with
water, then turn them over underwater so that their rims are
touching the bottom of the container and they're still full of
water.

3. Get two pieces of wire long enough to reach from the bottom of the
pot to your power supply connector.

4. Strip one end of both wires and slip the stripped ends under the
rims of the glasses without letting any air get into the glasses.
One wire per glass, and make sure the stripped ends don't stick out
from under the glasses.

5. Strip the other ends and connect them to your power supply.
Gas bubbles should begin forming on the stripped ends of the wires
under the glasses.

6. Let everything keep going until enough gas has collected in the
glasses so that you can clearly see that one glass has twice as
much gas in it as the other. The wire under that glass (the one
with twice as moch gas in it) will be connected to the negative
terminal of your power supply.
Click to expand...
The positive electrode will release oxygen an the negative will
release hydrogen. There will be twice as much hydrogen as oxygen.
More bubbles = negative.

--
John Popelish
 
John Fields wrote:
On Wed, 22 Dec 2004 12:10:40 -0500, John Popelish <jpopelish@rica.net
wrote:

The positive electrode will release oxygen an the negative will
release hydrogen. There will be twice as much hydrogen as oxygen.
More bubbles = negative.

---
Yeah, I know, but I didn't see anything linking the quantity of gases
evolved with the polarity of the electrodes. Maybe I missed it...
Click to expand...
I think it is implied because 2*H2O becomes 2*H2 and 1*O2. H20 has
twice as many hydrogen atoms as oxygen atoms. Split it and you get
twice as much hydrogen as oxygen.

--
John Popelish
 
"Rheilly Phoull" <Rheilly@bigpong.com> wrote in message
news:32t6pmF3pd57hU1@individual.net...
"Joe McElvenney" <ximac@btinternet.com> wrote in message
news:VA.00000070.003d52bb@btinternet.com...
Hi,

There is a question a little way up the group about a power
connector and which of the leads is positive/negative. Now
supposing you had the same problem with only the contents of the
average kitchen cupboard to hand, how would one go about
determining polarity?

I seem to remember from my school science classes of many
years ago, such things as gases bubbling off the end of wires
immersed in slightly acid solutions (vinegar and water) or maybe
electro-what's-it (as used in DNA matching) employing possibly
toilet paper and some easily to hand substance.

Any ideas ??


Cheers - Joe


I hear you but there are so many 'cheapo' digital meters around now
that
IMHO everyone should have one in the cupboard, much easier than making
solutions and handy for lots of situations.

--
Regards ..... Rheilly Phoull
Click to expand...
But in the not-so-real world of a homework problem, they don't have DMMs
in the cupboard. ;-)
 
On Sat, 25 Dec 2004 12:43:42 -0500, John Popelish <jpopelish@rica.net>
wrote:

stratus46@yahoo.com wrote:

Dumb question time. If you ran AC for the electrolysis, would you get
separated H and O in each glass? (one gas on each half cycle)


You get mixed H2 and O2.

Could be 'explosive'.

Very! Google [brown's gas].
___
Click to expand...

Back to the original post, here's an old chemist trick that works:
Dissolve salt in distilled water to make about a 5% solution. Take
about 1/2 cup of the solution and add 10 drops of phenolphthalein pH
indicator solution to it. Mix well and place it in an inert container
plastic or glass-the plastic 1/2 cup measuring cup works well. Clip a
couple of connectors(the insulated wire/alligator clip on both ends
type) to opposite ends of rim of the measuring cup. If needed raise
the level of liquid in the cup until its brim full-both alligator
clips must be touching the liquid. Now connect the other ends of the
connectors to the voltage source. Let stand undisturbed while
electrolysis produces a red-purple stain in the solution surrounding
one of the electrodes. That's the negative electrode. As the
electrolysis proceeds, the pH around the negative goes up, while the
pH around the positive electrode goes down. Whenever the pH reaches
about 8.3 it changes color from colorless to purple.
 
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