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Author: Subject: temperature about 6N HCl under reflux
whupharm_xu
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smile.gif posted on 26-4-2005 at 05:19
temperature about 6N HCl under reflux


to make a solution of 6N HCl reflux,what temperatre should be controlled?is it 100?
it seems to be above 120.anybody can tell me the exact one?
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tom haggen
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[*] posted on 26-4-2005 at 10:11


Just out of curiosity what do the units "N" stand for in chemistry? I know they are newtons in physics but chemistry I'm not quite sure because I haven't came across them yet.



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Mr. Wizard
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[*] posted on 26-4-2005 at 10:57


I believe it stands for Normal, which would be 1 Mole of a compound (6.023 x 10^23 molecules) in 1 liter of solution. This would allow you to measure out Moles of a substance by the convenient method of measuring it's volume. In the previous post the person's solution contains 6 Moles per liter or 6 times (1(H)+35(Cl)) or 216 grams (approx;)) in one liter of the solution. Assuming no dumb errors, that's it in a nutshell.

I had to correct molecules for atoms whoops:D

[Edited on 26-4-2005 by Mr. Wizard]




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tom haggen
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[*] posted on 26-4-2005 at 11:00


What you’re describing I know as molarity which is giving as mols/liter. Usually It's describe with a "M" but I guess "N" and "M" can be used interchangeably here.



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Mephisto
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[*] posted on 26-4-2005 at 12:05


whupharm_xu: Your 6 N HCl has a concentration of 22%. That's almost the concentration of the well known HCl-water-azeotrope, which boils at 108.58 °C and contains 20.22% HCl.

tom haggen: You've forgotten the equivalents. Normality isn't the same like Molarity, but you can say N = M * equivalents. 1 M HCl = 1 N HCl, but 1 M H2SO4 = 2 N H2SO4...




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Mr. Wizard
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[*] posted on 26-4-2005 at 15:43


I was off a little on Normal vs Molality. Normal is the Molal equivalents for acids and bases. Here are the details:
http://www.carolina.com/chemistry/experiments/review.asp




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tom haggen
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[*] posted on 26-4-2005 at 16:14


To tell you the truth this subject makes me want to through up.:P



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Mr. Wizard
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[*] posted on 26-4-2005 at 19:45


Quote:
Originally posted by tom haggen
To tell you the truth this subject makes me want to through up.:P

MEDGO= My Eyes Doth Glaze Over
:)




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whupharm_xu
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[*] posted on 26-4-2005 at 23:39


sorry,here i think, i must clarify that 6N HCl stands for 6 molar HCl in 1 liter water. hm... it's my neglect,and it is not a normal expression.:P
thank you for all!
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azaleaemerson
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[*] posted on 27-4-2005 at 05:06


Wouldn't heating up such a concentrated acid solution simply distill off the HCl? The acid solution already fumes, right?

Curious.




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cyclonite4
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[*] posted on 27-4-2005 at 05:16


IIRC, HCl forms a 20% azeotrope (fixed boiling point mixture) with water, and I think 6M is less than 20% HCl (too lazy/tired to calculate now). Hydrogen chloride won't just completely seperate from the water under heat.



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whupharm_xu
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[*] posted on 27-4-2005 at 07:48


i got 6M HCl by mixing concentrated HCl(36%-38%,about 12mol/l) with equivalent volum distilled water,is it right?:P
here heating a solution of 6M HCl under reflux is just to make ester hydrolyze,not to remove HCl with heating.
these days i carry out an experiment in hydrolyzing certain ester. the literature shows this ester is hydrolized with 6M HCl under reflux for about 12h. but today i have not got an promising result. i always suspect the hydrolyzation is not completely finished.possibly the temperature is not controlled right.
:Pi haven't mastered english well,maybe somebody can't understand clearly what i post.
sorry!
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[*] posted on 27-4-2005 at 08:25


Your ester changes the boiling point of the mixture too. If you only have to reflux your mix, let it simply boil and it controls its boiling point without your help.



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