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A question regarding different dilutions of HCl

mycologos

Greenlighter
Joined
Feb 28, 2012
Messages
2
hi all, i hope this is the right forum for this:
in an experiment i've been studying, there is the need for about 6.58 mL 37% HCl. i can only easily obtain 31.25% muriatic acid. i have calculated that there is .3784 grams less HCl and the same more water in the later at 6.58 mL. if i add another 1mL of 31.25% muriatic for a total of 7.58 mL i would then have an almost equal number of grams of HCL as in 6.58 mL 37% HCl (2.3687 g versus 2.4346 g), which would result in the same extraction results except for the extra water present in both the extra 5.75% difference between acids and with the addition of the extra 1 mL (.3784 g and .6875 g respectively for a total of an extra 1.0659 g of water, which is bad in this case). could this extra amount of water be removed by adding oven-dried epsom salts? these same dried salts can be used to make acetone anhydrous as called for in the experiement and i thought that i could also use it to remove the extra water in the HCl mentioned since it is intended to be mixed with the aforementioned dried acetone. i have read that 1 gram of dried epsom salts can absorb 1 gram of water, so after drying the acetone with the appropriate amount of dried epsom salts and filtering, could i add the HCL (with 1.0659 extra grams of water from the instructions due to the extra acid needed) and then add 1.0659 grams dried epsom salts to arrive at a HCl and acetone solution near equal to the one asked for with more concentrated HCl? i hope this makes sense and someone can help. thanks.

mycologos
 
i have read that 1 gram of dried epsom salts can absorb 1 gram of water,

This figure is incorrect. Anhydrous MgSO4 can absorb up to 10 moles of water per mole.

That said, yes, you can use MgSO4 as a drying agent, though it may be hard to seperate it from the resulting broth as it's water-soluble. It's mainly used for removing traces of water rather than larger amounts.
 
thanks seiko,

if that figure is so, can you please tell me how many grams of anhydrous MgSO4 i would need to absorb 1.0659 extra grams of H2O from my 31.25% muriatic acid?

i figured that 1.0659 g was, as you called it, a "trace" amount for a solution of say 250 mL (242.42 mL acetone + 7.58 mL 31.25% HCl). while the total water (5.2113 g) is a LOT for this experiment, 4.1454 g of it is accounted for in the instructions, so it is just the 1.0659 g from the more dilute muriatic i wish to remove, essentially making 37% HCl from 31.25% HCl in solution with anhydrous acetone by mixing in quantity of epsom salts (grams???).

if you, or anyone else, knows the answer i would be very grateful as it has been too long since i have dealt with moles.

thanks,

mycologos
 
What are you doing with said HCl soln?

Also, moles and stoichiometry is not advanced drug discussion, it's first-year chemistry.. go get a high school textbook or something
 
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