Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Coroded Electrical Contacts Restore

On Fri, 22 Nov 2013 05:07:11 -0800, "William Sommerwerck"
wrote:

"Geoffrey S. Mendelson" wrote in message
...

Remove the corrosion with vinegar or acid (ammonia)-
based window cleaner.


Ammonia is an alkali, not an acid. I've used household ammonia for years, and
never had problems. Once the contacts were cleaned, they stayed clean.

There are disagreements among us as to whether Energizers or Duracells are
more likely to leak. Every modern battery that has leaked in my equipment has
been a Duracell. I don't use them, unless they're the only batteries
available.


According to the chemists, ammonia is a weak acid. (So weak that some
think it is an alkali).
I recently found a duracell that leaked in something i have. Merely used
some window cleaner to remove the gunk. Shelf life OK, useful life once
installed questionable.

YMMV

?-)
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"josephkk" wrote in message
...

According to the chemists, ammonia is a weak acid.


According to the Wikipedia article, "One of the most characteristic properties
of ammonia is its basicity. Ammonia is considered to be a weak base."

It also says...

"Although ammonia is well known as a weak base, it can also act as an
//extremely// weak acid. It is a protic substance and is capable of formation
of amides (which contain the NH2ˆ’ ion)."

So it appears to depend on the reaction.


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Here's something else from Wikipedia. Remember litmus paper?

"The main use of litmus is to test whether a solution is acidic or basic. Wet
litmus paper can also be used to test water-soluble gases; the gas dissolves
in the water and the resulting solution colors the litmus paper. For instance,
ammonia gas, which is alkaline, colors the red litmus paper blue."

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On Wed, 18 Dec 2013 03:22:34 -0800, "William Sommerwerck"
wrote:

Here's something else from Wikipedia. Remember litmus paper?

"The main use of litmus is to test whether a solution is acidic or basic. Wet
litmus paper can also be used to test water-soluble gases; the gas dissolves
in the water and the resulting solution colors the litmus paper. For instance,
ammonia gas, which is alkaline, colors the red litmus paper blue."


Well you are allowed to trot out all the low grade references you wish. Do
better fact checking and you will find out that ammonia is indeed a weak
acid. See also Lewis acid e. g. BF3 which has no hydrogen at all.

?-)
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"josephkk" wrote in message
...
On Wed, 18 Dec 2013 03:22:34 -0800, "William Sommerwerck"
wrote:

Here's something else from Wikipedia. Remember litmus paper?


"The main use of litmus is to test whether a solution is acidic or basic.
Wet
litmus paper can also be used to test water-soluble gases; the gas
dissolves
in the water and the resulting solution colors the litmus paper. For
instance,
ammonia gas, which is alkaline, colors the red litmus paper blue."


Well you are allowed to trot out all the low grade references you wish. Do
better fact checking and you will find out that ammonia is indeed a weak
acid. See also Lewis acid e. g. BF3 which has no hydrogen at all.


To call Wikipedia a low-grade reference is a cheap shot. As for fact-checking,
do some yourself.



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William Sommerwerck wrote:
"josephkk" wrote in message


Well you are allowed to trot out all the low grade references you wish. Do
better fact checking and you will find out that ammonia is indeed a weak
acid. See also Lewis acid e. g. BF3 which has no hydrogen at all.


To call Wikipedia a low-grade reference is a cheap shot. As for fact-checking,
do some yourself.


http://www.chem.queensu.ca/people/fa...base/index.htm
http://www.uwec.edu/lewisd/Chem321-0...-Base/Acid.htm
http://www.bbc.co.uk/bitesize/higher...ds/revision/1/
http://www.files.chem.vt.edu/chem-ed...ase/intro.html

These consistently identify ammonia (NH3) as a weak base, according to
the Bronsted-Lowry definition.

When NH3 reacts with water, the NH3 accepts a proton from the water
and generates the ammonium ion (NH4+, a weak acid), and the hydroxide
ion (OH-). The fact that NH3 accepts a proton in this reaction is
what defines it as a Bronsted-Lowry base.

According to

http://www.scienceforums.net/topic/4...mmonia-a-base/

NH3 is at least somewhat amphiprotic - in some reactions it can donate
a proton (acting as an acid) rather than accepting one.

According to

http://www.chem1.com/acad/webtext/abcon/abcon-6.html

"ammonia, is a weaker acid than H2O, so it exhibits basic properties
in water

NH3 + H2O †’ NH4+ + OH€“

but behaves as an acid in non-aqueous solvents such as liquid ammonia
itself:

NH3 + NH3 †’ NH4+ + NH2€“ "

and also says

"Ammonia is such a weak acid that its conjugate base, amide ion NH2€“,
cannot exist in water. In aqueous solution, NH3 acts as a weak base,
accepting a proton from water and leaving a OH€“ ion"

So, the answer to the question "Is ammonia a base or an acid" appears
to be "either or both, depending on the circumstances."

It's not an either/or sort of thing.
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On 12/21/2013 08:34 PM, David Platt wrote:
William Sommerwerck wrote:
"josephkk" wrote in message


Well you are allowed to trot out all the low grade references you wish. Do
better fact checking and you will find out that ammonia is indeed a weak
acid. See also Lewis acid e. g. BF3 which has no hydrogen at all.


To call Wikipedia a low-grade reference is a cheap shot. As for fact-checking,
do some yourself.


http://www.chem.queensu.ca/people/fa...base/index.htm
http://www.uwec.edu/lewisd/Chem321-0...-Base/Acid.htm
http://www.bbc.co.uk/bitesize/higher...ds/revision/1/
http://www.files.chem.vt.edu/chem-ed...ase/intro.html

These consistently identify ammonia (NH3) as a weak base, according to
the Bronsted-Lowry definition.

When NH3 reacts with water, the NH3 accepts a proton from the water
and generates the ammonium ion (NH4+, a weak acid), and the hydroxide
ion (OH-). The fact that NH3 accepts a proton in this reaction is
what defines it as a Bronsted-Lowry base.

According to

http://www.scienceforums.net/topic/4...mmonia-a-base/

NH3 is at least somewhat amphiprotic - in some reactions it can donate
a proton (acting as an acid) rather than accepting one.

According to

http://www.chem1.com/acad/webtext/abcon/abcon-6.html

"ammonia, is a weaker acid than H2O, so it exhibits basic properties
in water

NH3 + H2O †’ NH4+ + OH€“

but behaves as an acid in non-aqueous solvents such as liquid ammonia
itself:

NH3 + NH3 †’ NH4+ + NH2€“ "

and also says

"Ammonia is such a weak acid that its conjugate base, amide ion NH2€“,
cannot exist in water. In aqueous solution, NH3 acts as a weak base,
accepting a proton from water and leaving a OH€“ ion"

So, the answer to the question "Is ammonia a base or an acid" appears
to be "either or both, depending on the circumstances."

It's not an either/or sort of thing.


It's great for shining brass!
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"David Platt" wrote in message ...

So, the answer to the question "Is ammonia a base or an acid" appears
to be "either or both, depending on the circumstances."


Thank you for taking the time to clarify this.
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On Sat, 21 Dec 2013 20:34:56 -0800, (David Platt)
wrote:

William Sommerwerck wrote:
"josephkk" wrote in message


Well you are allowed to trot out all the low grade references you wish. Do
better fact checking and you will find out that ammonia is indeed a weak
acid. See also Lewis acid e. g. BF3 which has no hydrogen at all.


To call Wikipedia a low-grade reference is a cheap shot. As for fact-checking,
do some yourself.


http://www.chem.queensu.ca/people/fa...base/index.htm
http://www.uwec.edu/lewisd/Chem321-0...-Base/Acid.htm
http://www.bbc.co.uk/bitesize/higher...ds/revision/1/
http://www.files.chem.vt.edu/chem-ed...ase/intro.html

Interesting. I am corrected, more or less. It was another earlier odd
change to shift from thinking of it a weak base to a very weak acid. It
took about the same grade of information then as well.

These consistently identify ammonia (NH3) as a weak base, according to
the Bronsted-Lowry definition.

When NH3 reacts with water, the NH3 accepts a proton from the water
and generates the ammonium ion (NH4+, a weak acid), and the hydroxide
ion (OH-). The fact that NH3 accepts a proton in this reaction is
what defines it as a Bronsted-Lowry base.

According to

http://www.scienceforums.net/topic/4...mmonia-a-base/

NH3 is at least somewhat amphiprotic - in some reactions it can donate
a proton (acting as an acid) rather than accepting one.

According to

http://www.chem1.com/acad/webtext/abcon/abcon-6.html

"ammonia, is a weaker acid than H2O, so it exhibits basic properties
in water

NH3 + H2O †’ NH4+ + OH€“

but behaves as an acid in non-aqueous solvents such as liquid ammonia
itself:

NH3 + NH3 †’ NH4+ + NH2€“ "

and also says

"Ammonia is such a weak acid that its conjugate base, amide ion NH2€“,
cannot exist in water. In aqueous solution, NH3 acts as a weak base,
accepting a proton from water and leaving a OH€“ ion"

So, the answer to the question "Is ammonia a base or an acid" appears
to be "either or both, depending on the circumstances."

It's not an either/or sort of thing.

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"josephkk" wrote in message
...

Interesting. I am corrected, more or less. It was another
earlier odd change to shift from thinking of it a weak base
to a very weak acid. It took about the same grade of
information then as well.


And I admit to being surprised that such a simple molecule can be a proton
receptor under one set of conditions, a donor under others.



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