Sciencemadness Discussion Board

Muriatic Acid

JJay - 21-1-2016 at 19:09

I am going to make some ACS grade hydrochloric acid in the forseeable future by gassing purified water with hydrogen chloride to produce a saturated solution, but today I was looking for a more dilute solution and titrated some Klean Strip muriatic acid from Walmart. It was advertised as producing fewer fumes than regular muriatic acid, so I had low expectations, but it was very inexpensive. The titration said that the concentration is 6.554 M.

Two questions:

1. Is this a reasonable result for Klean Strip muriatic acid?
2. Is there some better brand of muriatic acid I can buy? Desirable qualities include high HCl concentration and low impurities.

[Edited on 22-1-2016 by JJay]

j_sum1 - 21-1-2016 at 19:36

I can't speak for US brands. In Aus, hardware store hydrochloric acid is crystal clear, clean and very pure. IME it titrates out at between 9.5 and 10.5M

Muriatic acid is remarkably easy to clean by putting open beakers of water and acid in a sealed plastic container and leaving it for a while. This method is at the expense of concentration. Azeotropic distillation is your next option and I believe is simple and works well although I have not tried it.

So,
1. 6.5M for something that aims to be low fuming is ok if you know what you are getting. I think higher concs are possible with few fumes.
2. Dunno.

Dr.Bob - 21-1-2016 at 19:47

Many places sell nearly pure muriatic acid, pool chem companies, industrial supplies companies, janitorial supplies, and many hardware stores. Conc HCl is normally about 12 M, so you have roughly 50% Conc HCl in water, so that is good for many cleaning purposes, but you should be able to buy conc HCl somewhere that is twice that, and won't need purifying.

Try googling your area/location and muriatic acid or industrial supplies, etc. Not that distilling HCl is not a great chemistry lesson, but once you have done that, you may want to buy it in the future. Good luck.

JJay - 21-1-2016 at 19:54

I can buy ACS grade from one of the local chemical supply houses, but one of them charges an arm and a leg for it, and the other merely wants me to trade my firstborn child for 500 mL (ok, actually they only charge about $90 for 500 mL, but that's outrageous). So I'm looking at hardware stores, paint stores, etc.

byko3y - 21-1-2016 at 21:33

FFS, HCl is extreemely easy to purify with any simple device, while any concentration can be achieved using CaCl2 or any other suitable water entrainer. Until you have a noticable amount of As or Br in the source materials. The first is removed using SnCl2, the second one is removed either from solution by distillation (HBr is less volatile), or from the salt using any chlorine source and evaporating both the chlorine and freed bromine.

mayko - 21-1-2016 at 21:52

I have never personally measured the concentration of 'low fuming' HCl, but people who use it as pool pH down seem to say that it is relatively dilute; see here:
http://www.sciencemadness.org/talk/viewthread.php?tid=63422#...

JJay - 21-1-2016 at 22:07

Quote: Originally posted by mayko  
I have never personally measured the concentration of 'low fuming' HCl, but people who use it as pool pH down seem to say that it is relatively dilute; see here:
http://www.sciencemadness.org/talk/viewthread.php?tid=63422#...


That is the exact same brand; it does have mixed reviews, and people are saying that it is about 20%, so it looks like my titration is in the right ballpark.

JJay - 21-1-2016 at 22:12

Quote: Originally posted by byko3y  
FFS, HCl is extreemely easy to purify with any simple device, while any concentration can be achieved using CaCl2 or any other suitable water entrainer. Until you have a noticable amount of As or Br in the source materials. The first is removed using SnCl2, the second one is removed either from solution by distillation (HBr is less volatile), or from the salt using any chlorine source and evaporating both the chlorine and freed bromine.


I might give concentration with CaCl2 a try. I suspect it's going to be very hard to produce ACS grade hydrochloric acid without some gassing, though.

CharlieA - 22-1-2016 at 14:21

JJay
I bought recently: 1 gal Muriatic Acid, JASCO; "etches concrete; lowers swimming pool pH. 20* Be; 31.5% by wt. per label. This is 10M and appears to be reasonably clean. I have the MSDS, but I don't know how to attach it to this post. I think I bought it from Ace Hardware, but now I am not sure. The manufacturer is W. M. Barr Co. I can send you the MSDS as a pdf if you send me your email adress (or can I attach it to a U2U?).-Charlie

arkoma - 22-1-2016 at 17:14

Tractor Supply. Crystal clear for about $7/gallon

*edit*

W. M. Barr brand also per above post

[Edited on 1-23-2016 by arkoma]

PlatinumLab - 22-1-2016 at 18:05

JJay may I ask what region you live in? The Walmart near me doesn't sell hydrochloric acid. I can only find it at hardware stores and it is very concentrated. I find it nearly impossible to work with outside of a fumehood or outside due to the intense fumes it produces when pouring. I would love to get my hands on a diluted form of it.

JJay - 22-1-2016 at 19:34

It's in the paint section... I live in the northwest USA.

I've handled ACS grade hydrochloric acid outside of a fume hood lots of times without issue, but breathing the fumes should be avoided. I'll definitely check Ace Hardware for muriatic acid.

PlatinumLab - 22-1-2016 at 19:48

The hydrochloric acid they sell at my hardware store is very concentrated. Even tapping the side of it with the lid open causes fumes to come pouring over the sides. The brand you're talking about is Klean Strip? I may have to take another look at Walmart, since I may have missed it.