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View Full Version : Need a Chemist, Acetic acid (white vinegar) and salt solution percentage


Hobster
11/02/2015, 02:20 PM
From what I have researched ( for a cleaning solution)

If white vinegar is mixed with some table salt it forms a form of HCL

Now I have cleaned pumps and such with a 10:1 (water to muriatic acid)

Can anyone give me a rough percentage of what 16 oz of 5% vinegar and 2 tablespoons of table salt to make 1 gallon of water solution would be??

I am only guessing but it seems it would be a very weak acid solution and much less than my 10 parts water and 1 part pool muriatic acid.

What I am looking for is the percentage of the final vinegar/salt/water to make 1 gal.

Thank you

Hope this makes sense.:)

bertoni
11/02/2015, 08:07 PM
I don't believe that adding salt will change the cleaning efficiency, depending on what you're trying to remove. To remove calcium carbonate, adding salt shouldn't have any noticeable effect.

Hobster
11/02/2015, 10:20 PM
Perhaps not but what I really am interested in determining is what is the percent of the final solution.

If adding salt to the vinegar produces a mild HCL is that not a stronger acid than just acetic acid for cleaning calcium build up.

To make it easier, lets forget the salt.
What is the percent if I add 16 oz of 5% vinegar to 112 oz of water to make 1 gallon??

Thanks

bertoni
11/02/2015, 10:23 PM
I don't think adding salt will create any equivalent of using HCl. That's not making sense to me yet.

I think I understand the question now. You are considering adding water to 16 oz of standard, enough to make a gallon. You'd like to know an equivalent concentration that could be made using HCl?

Hobster
11/02/2015, 10:53 PM
I don't think adding salt will create any equivalent of using HCl. That's not making sense to me yet.

I think I understand the question now. You are considering adding water to 16 oz of standard, enough to make a gallon. You'd like to know an equivalent concentration that could be made using HCl?

No;)

Just what is the percent of 2 cups of vinegar in 112 oz of water

IE: what is the final percent of acetic acid. Would it be a .05% .1 %., .2% final concentration??

Dan_P
11/03/2015, 02:50 AM
From what I have researched ( for a cleaning solution)

If white vinegar is mixed with some table salt it forms a form of HCL

Now I have cleaned pumps and such with a 10:1 (water to muriatic acid)

Can anyone give me a rough percentage of what 16 oz of 5% vinegar and 2 tablespoons of table salt to make 1 gallon of water solution would be??

I am only guessing but it seems it would be a very weak acid solution and much less than my 10 parts water and 1 part pool muriatic acid.

What I am looking for is the percentage of the final vinegar/salt/water to make 1 gal.

Thank you

Hope this makes sense.:)

Sounds like a college Freshman chemistry question.

Adding sodium chloride to vinegar will not reduce the pH, that is, make the soluion more acidic. Just because there is a chloride ion in solution does not make hydrochloric acid. That is why saline solutions for eye washes don't burn the eye or salting food does not make it sour.

The choride ion is actually a very, very weak base. If it were to have an effect, it would be to raise the pH by taking up a proton, though this pH change cannot be observed in water. You are correct that vinegar is a weaker acid solution than dilute muriatic acid, but sodium chloride does not increase the acidity.

toothybugs
11/03/2015, 06:11 AM
No;)

Just what is the percent of 2 cups of vinegar in 112 oz of water

IE: what is the final percent of acetic acid. Would it be a .05% .1 %., .2% final concentration??

Let me try this:

Assuming 5% acetic acid in 2 cups (aka 16oz) diluted with an additional 112oz, you are diluting the initial amount to 1/8 original concentration. So 5% div by 8 = 0.625% acetic acid. Figuring for inaccuracy in measure (short weighs, etc) say 0.5-0.6% effectively.

It's too early in the morning for me to go through the molarity conversions and Ka calculations to find you the pH, but that would be a really weak solution.

Hobster
11/03/2015, 07:44 AM
Thank you! That is close enough for Govt work;)

What brought this "debate" up was that by mixing the salt with the vinegar it produced HCL, as far as my "research" that is correct.

But as stated the acidity of the HCL is not more potent than just the acidic acid. May be a different acid, but not stronger.

Pretty much I do not believe you can make a strong acid out of a weak one.

PS: It has been a hundred years since I took Freshman Chemistry:fun2:

disc1
11/03/2015, 09:07 AM
Mixing salt into acetic acid doesn't really produce HCl. HCl is a strong acid because it completely dissociates, it doesn't have anything to do with the chloride.

You are correct that mixing acetic acid and sodium chloride gtes you the same solution as mixing HCl and sodium acetate. But that's not quite the same as creating HCl. You can't turn a weaker acid into a stronger acid by adding the stronger acids counter ion. You still have the weak acid in there controlling the pH.

CStrickland
11/03/2015, 09:20 AM
if adding salt to vinegar made HCl I would have burned off my hands polishing the silver a long time ago

Hobster
11/03/2015, 09:31 AM
I do not know. Get it from the web so it must be true:lol:


YES I know we do not want copper in a marine fish tank!!

Cleaning copper pennies or something.

HC2H3O2 + NaCl ---> HCl + NaCH3O2
(vinegar) + (salt) ---> (hydrochloric acid) + (sodium acetate)

Reaction with copper penny

The salt is added to vinegar to speed up the process.
Addition of NaCl to vinegar shifts the equilibrium of acid dissociation, i.e. CH3COOH↽−−⇀CH3COO−+H+, to right therefore concentration of H+ & CH3COO− increases. Due to this, NaCl reacts with CH3COOH to give HCl
NaCl+CH3COOH↽−−⇀CH3COONa+HCl
Cooper Oxide (base) reacts with acids to form water and copper salts.
Acetic acid (CH3COOH), which is a weak acid, will react slowly with Copper oxide as compared to HCl which is strong acid.
So when use vinegar-salt solution to clean penny, Copper Oxide parellely reacts with HCl and CH3COOH both and gives Copper salt and water.
CuO+CH3COOH⟶2H20+Cu(C2H3O2)2
CuO+2HCl⟶H2O+CuCl2

dkeller_nc
11/03/2015, 09:39 AM
As David notes, the reason that HCl is a stronger acid than acetic is that the dissociation constant difference between the two shifts the equilibrium to the hydronium ion and complementary base much more strongly with HCl.

However, what laypersons think of as the "strength" of acid is a bit different. Typically, folks interpret the strength of a particular acid as the concentration, and therefore the effectiveness of said acid solution in dissolving ionic compounds, etching metals, or chemically burning one's skin. Very concentrated acetic acid, for example, can give you a very bad chemical burn, while one can actually drink sufficiently dilute hydrochloric acid (believe it or not, diluting HCl and tasting it used to be a standard chemistry exercise in HS chemistry class).

But with respect to making up a cleaning solution for the typical job of removing calcium carbonate from reef equipment, it's far, far cheaper to purchase a bottle of concentrated HCl from a pool supply outlet than it is to use vinegar. 0.1N HCl is very effective at rapidly removing calcium carbonate build-up, and since the bottle contains 12N HCl, one dilutes it approximately 100 to 1 with water - that's a lot of cleaning solution for very little money.

Hobster
11/03/2015, 10:31 AM
Well to be honest, I have been using the 10:1 water to HCL since Randy was around some time ago.

This question is really OT but it was for cleaning brass, copper but this was the only place I knew Chemist hung out!;) Used to be able to PM Randy and Boomer about these things,

The debate was that adding salt to the vinegar would create HCL and harm the brass. I figured it was so weak a dilution it would not matter. Pretty much like using another acid like citric acid, oxalic or phosphoric. If it is dilute enough and not prolonged contact, then I do not think it harms anything.

HCL is actually stomach acid.:D

Thanks for all the help

disc1
11/03/2015, 03:43 PM
I do not know. Get it from the web so it must be true:lol:


YES I know we do not want copper in a marine fish tank!!

Cleaning copper pennies or something.

HC2H3O2 + NaCl ---> HCl + NaCH3O2
(vinegar) + (salt) ---> (hydrochloric acid) + (sodium acetate)



I guess you can't believe everything you read on the internet can you?

The proper reaction in water would have all of those things dissociated on the right side. (and they've not been to many classes or they'd write vinegar the way chemists do)


CH3COOH + NaCl ---dissolved in water---> H+ + CH3COO- + Na+ + Cl-

disc1
11/03/2015, 03:48 PM
You're not "making "HCl". You are making the same thing you would have made had you started with HCl and neutralized part of it by sodium acetate. But the acid all came from the vinegar, you're not adding any more acid or making it any stronger by adding the salt. The only acid there is what came from the vinegar. The strength of the acid will be the same with or without the salt.

All you've really made is salty vinegar. Great for pickles.

Quiet_Ivy
11/03/2015, 04:53 PM
if adding salt to vinegar made HCl I would have burned off my hands polishing the silver a long time ago

Rofl, this year my Dad had a metric buttload of cukes and I made 10 jars of pickles. We don't have pickling lime in this country (no I don't know why) so I used a whole lotta vinegar, salt and CaCl. I sure hope they don't turn into HCl, it'll ruin the taste. I was hoping a chemist would chime in here.

ivy

Hobster
11/03/2015, 04:59 PM
How about vinegar and salt potato chips?:D

Dan_P
11/03/2015, 05:12 PM
Well to be honest, I have been using the 10:1 water to HCL since Randy was around some time ago.

This question is really OT but it was for cleaning brass, copper but this was the only place I knew Chemist hung out!;) Used to be able to PM Randy and Boomer about these things,

The debate was that adding salt to the vinegar would create HCL and harm the brass. I figured it was so weak a dilution it would not matter. Pretty much like using another acid like citric acid, oxalic or phosphoric. If it is dilute enough and not prolonged contact, then I do not think it harms anything.

HCL is actually stomach acid.:D

Thanks for all the help

Chloride ion enhances the corrosion of copper, so, acetic acid plus sodium chloride would act like it was more corrosive than acetic acid alone, but it is not because it generates HCl.

dkeller_nc
11/04/2015, 07:25 AM
Well to be honest, I have been using the 10:1 water to HCL since Randy was around some time ago.


I'd suggest that you might want to consider 100:1. A 10:1 dilution of concentrated HCl will give you a solution that's about 1.2N. HCl that strong will pretty much instantly burn your skin. 0.12N HCl gives you a chance to rinse it off before it does much damage (though it will still burn if left on your skin for a number of minutes).

You should use a fine abrasive polish to clean tarnish off of brass/copper rather than a chemical dip. Items that can't be polished in this way because of the object's shape and/or rough surface should be cleaned with a dilute ammonia solution, not an acid. While an acid wash is effective on a brass surface, it can cause pitting on the surface due to differential dissolution of zinc in the brass alloy. That pitting provides an ideal environment for further corrosion.