Hardware Store Hydrochloric Acid - How to Purify

"The two containers of liquid achieve equilibrium when the concentration of HCl in both containers is identical. So, for example, if you started with 100mL of 31% HCl and 100mL of distilled water, you'd end up with both containers being 15.5% (less some loss to the air). With 100mL of 31% HCl and 1mL of distilled water, both containers would be very slightly less than 31%."

Thanks for that post - you've solved my problem - locked down in Canada. I'll kick out a batch soon - I'm just about out of my 4% made with hardware acid.

My chemisty is pathetic. What would the ratio of ml of HCL 31.45% to ml of distilled water placed in the fume container to produce ~ 4% HCL. A one step process would be wonderful.

Hi Martin. I had downloaded that video a year or so ago, but forgot about it until last night when I was looking for another video on a hard drive. I need a dilution calculator to figure things out, too!

endmemo.com/bio/dilution.php Use the last calculator and change to %. There will be some loss of HCL into air so you will get less. Save some of your current 4% and compare ppm with the new 4% is the only way I know how to be sort of sure you have 4%.

If this doesn't work, then I would try equal amounts of DW in both containers and use the dilution calculator to get 4% from 31.45%. In that case you would combine 686.25 DW with the 100ml of 31.45% HCL from the distilled water container to end up with 786.25ml of 4%. Always add the acid to the water.

There is a way to determine HCL % but is not easy. www.marz-kreations.com/Chemistry/Analysis/Quantitative/167f-Conc_HydroChloricAcid.html If you figure this out, let me know. :)