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Topic: HCL and H20  (Read 16424 times)

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RLA_100

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HCL and H20
« on: September 29, 2004, 03:02:18 AM »
Just a question i've always wondered.
Since HCL + H20 dissassociates 100% into H30 and CL-  than theortically if you had pure HCL and poured it on your skin it would do no damage?

Also how the more water you add the less acidic it is, dosen't more water allow more Hyrdonium Ions to form?

Offline AWK

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Re:HCL and H20
« Reply #1 on: September 29, 2004, 04:18:43 AM »
Boiling point of pure HCl is -85 C. How would you pour it on you skin?

the more water - the more diluted solution of hydronium ions.
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Offline jdurg

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Re:HCL and H20
« Reply #2 on: September 29, 2004, 10:48:09 AM »
More water will allow more hydronium ions to form, but only if there is more acid available to form the hydronium ions.  If you have four moles of HCl in 5 moles of water, adding more water won't create more HCl.  Acidity is determined by the concentration of hydronium ions in a solution, and adding more water only dilutes the concentration, thus reducing the acidity.  Also, if you had pure HCl and poured it on your skin, first off the very low temperature of the liquid HCl would caused a lot of damage to your skin, and the HCl would also draw water out of your skin causing a lot of damage.  It's the same principal as if you spilled powdered NaOH on your skin.
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RLA_100

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Re:HCL and H20
« Reply #3 on: September 29, 2004, 06:15:07 PM »
Hi thank you for respond,

So if you have 4 mol's of HCL and add 1 mol of H20 the acidty wont' be as high as if you had 4 mol HCL and 4 mol H20?


Offline AWK

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Re:HCL and H20
« Reply #4 on: September 30, 2004, 02:05:20 AM »
In this case acidity will be almost the same since you can dissolve only about 1/3 mole of HCl in 1 mole of water at RT. Highest pressure of HCl over solution increase solubility of HCl (and pH) insignificantly for the first case.
But if you take 4 mole of HCl for 1 L of water or 4 mole of HCl for 4 L of water the difference of pH will be about 0.6 unit.
« Last Edit: September 30, 2004, 02:11:52 AM by AWK »
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Offline movies

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Re:HCL and H20
« Reply #5 on: September 30, 2004, 01:31:15 PM »
Sorry for this off-point digression:

So is "acidity" a bulk property, analogous to pH?  So dependent on concentration.  Or is it a molecular property based on some standard concentration.

For example, if I have a solution of acetic acid with a pH of 1 and a solution of sulfuric acid with a pH of one, do those solutions have the same "acidity"?  I always think of sulfuric acid as more "acidic" than acetic acid, but I've never really thought about it that much.

Offline AWK

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Re:HCL and H20
« Reply #6 on: October 01, 2004, 03:43:44 AM »
Movies are extremely precise.
I used "acidity" as a synonym of pH incorectly (if not bracketed), but fortunately I did not compare different acids but only different concentration of the same acid.
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