The Home Scientist 007 - Purify hydrochloric acid

In this segment of the continuing "chemicals on the cheap" series, we purify technical grade hydrochloric acid--available cheaply by the gallon in home improvement centers--using only three plastic containers and with about two minutes' work. The resulting hydrochloric acid is as pure as reagent grade acid. The downside is that the process takes a week or two to finish, and the resulting reagent-grade acid is about 5 molar rather than the 12 molar typical of commercial concentrated hydrochloric acid. Still, it's extremely pure and concentrated enough for most purposes.

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[ABOlsen69666]

What is the PH diff. between the technical grade 30-32% acid and the reagent grade 38-39%+ acid?

[TheHomeScientist]

@ABOlsen69666

Not much. The pH of 31.45% (10 molar) acid is -1.0. The pH of 36% to 38% is -1.1.

[TakronRust]

If you started with 100ml of technical grade on your emitter and 50ml in your collector, wouldn't you get 5.1M in your emitter and 10.2 in your collector? Seeing as the volume is half so the concentration would be double with the same vapor pressure.

[TheHomeScientist]

@TakronRust

No, that's not how equilibrium and vapor pressure work. Regardless of the volumes in the two vessels, at equilibrium the concentration will be the same in both.

[collura1]

I have 32% reagent grade Hydrochloric acid. I'm trying to get a 20.2% HCL, 29.8% H2O and 50%Alcohol mixture. Would it be possible to use this method by adding x% (I guess 50%) distilled water and 99.9% alcohol in the reagent jar? Maybe I can get to 20.2% HCL after doing this twice. Would this be the same as starting out with 40.4% HCL?

[TheHomeScientist]

@collura1

The 32% is m/m. 100 grams of the solution contains 32 grams of HCl. Ordinarily alcohol (ethanol and isopropanol, anyway) mixtures are v/v. Combining 100 mL of water with 100 mL of absolute ethanol or isopropanol yields a 50% v/v mixture. Unfortunately, volumes aren't additive. That is, mixing 100 mL of each doesn't give you 200 mL of solution. Also, the water/alcohol solution is less dense than water or the HCl solution, so the m/m percentage of HCl changes.

[cyberlightbeing]

Hi, thanks for the video. The result that is very purified HCL can it be regarded as a 'food grade' HCL?

[carlip]

would adding heat speed the process?

[cybob43]

unless reagent grade HCI dose not react with aluminum this does not work. the distilled water container contained 80 ml of ???? the muratic acid container still reacted with aluminum and the reagent grade hci did not

[keglimp]

this is a great video!! thanks heaps!!

[TerminalRhinoVirus]

@Zanragnar You are correct in saying it will dilute the acid, however, the purpose is to eliminate impurities often found in technical grade HCl acid.

So you are left with, as he said, two solutions of 5.1 M HCl acid from the original 10.2 M solution.

[Zanragnar]

Doesn't this dilute the acid, as the HCl is being split between the two containers?

[Tutorializer100]

Hmm.... Ot does not burn on my skin but tastes like salt

[MrPaneKe]

and what amount of both and water?

[MrPaneKe]

can i make pure ammonia(28-30%) or concentrated hydrochlorid acid (37,5%) by bubbling anhydrous ammonia gas or hydrogen chloride gas respectively into a water container?