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NEMO-Chemistry
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0.1M HCl questions
I need to make up a stock solution of approx 200ml 0.1 HCl.
First question is a check of my maths....
Starting with 36.5% HCl
room temp and water temp around 5C
Roughly add 180ml DW to volumetric flask
Add 1.69ml of HCL to flask
Then top up to line with approx another 8.3ml DW
This should give me a approx 0.1M solution??
Storage.......
HCl is a bastard for rusting stuff, the bottle i need to store this in is a old glass lab bottle (ground glass), can i use a normal ground glass
stopper or rubber bung to store this in? Or do i need to get creative to stop it escaping?
I am only needing it around for a week or so.
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The Austrian Scientist
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Yes, but to be precise you need to add 2 mL of conc. HCl.
Storage of the 0,1 M solution shouldn´t be a problem since the HCl is very dilute and not much HCl vapours are ecaping.
[Edited on 2-1-2018 by The Austrian Scientist]
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ninhydric1
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As The Austrian Scientist said, it shouldn't be a problem. If you are really afraid that HCl gas could leak out, put some Teflon or electrical tape
around the seam during storage. I do this if I'm storing concentrated (37%) HCl, or 2.0 M or higher.
The philosophy of one century is the common sense of the next.
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NEMO-Chemistry
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Thx guys
Shit my maths was off! Not that it matters for this, its only got to be 'about' 0.1M.
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Sulaiman
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The main unknown is the original HCl concentration,
you can titrate the original acid, or better, the dilluted product - e.g. vs. sodium carbonate
in theory (I've not tried) you could diute the HCl to about 20.2% w/w and boil it until a constant temperature is achieved - you should then be sure
to have Azeotropic HCl
CAUTION : Hobby Chemist, not Professional or even Amateur
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aga
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I think the constant boiling point would be just water.
The bit boiling off at 108 C would be around 20% conc. HCl.
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happyfooddance
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I never use this, but https://www.sigmaaldrich.com/chemistry/stockroom-reagents/le...
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JJay
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Sulaiman is correct. You can actually know the concentration of the HCl very precisely if you know the barometric pressure.
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The Austrian Scientist
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For such calculations I got an app on my phone.
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NEMO-Chemistry
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I got a hydrometer?
I didnt think about getting an app on the tablet! In this case the numbers dont have to be ultra precise. I was more concerned I would be a decimal
point off lol.
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aga
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Stick a measuring cylinder on some scales, tare them, then measure out 10ml and record the weight.
That'll give you the approximate density.
Wiki has a table https://en.wikipedia.org/wiki/Hydrochloric_acid that will give you an approximate w% based on that density.
It will probably be around 36 w% like it says on the bottle, although that kind of FUMING HCl concentration i have never seen available anywhere (max
i got is 32 w%).
With a w% figure and density (and the m.w.) you can work out the [M] of your HCl, then use th C1V1 = C2V2 formula to work out how much water to add to
get to your target concentration.
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happyfooddance
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http://www.handymath.com/cgi-bin/hcltble3.cgi?submit=Entry
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unionised
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Strictly, you missed a bit
Add 1.69ml of HCl to flask
Wait for it to cool
Then top up to line with approx another 8.3ml DW
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happyfooddance
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Quote: Originally posted by unionised  |
Strictly, you missed a bit
Add 1.69ml of HCl to flask
Wait for it to cool
Then top up to line with approx another 8.3ml DW
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Why would it need to cool unless he was adding dry HCl(g)?
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NEMO-Chemistry
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Because i took the temperature into consideration as it was a long way from normal room temp.
Unionised helps me by pointing out the little bits I miss. He isnt being pedantic, he is just aware I like to know all the wrinkles and details
without a full blown analysis.
While this particular procedure didnt have to be spot on, i was trying to make sure I had the procedure right. I have some more to do later next week,
those need to be more accurate.
I no longer own a measuring cylinder aga.... i need to rectify that, yet AGAIN!! Time to splash out on a couple of those bumper ring things  .
The acid origanaly came from ACP Pure around 18 months ago, i brought 15 ltrs in 3 X 5ltr containers. This is a new one i just opened. Back when I got
it, they were all marked 36.6%, but i notice on the site now they have put a range.
Mine however does have the analysis report on the label.
Not much help to you in spain but just in case
https://apcpure.com/product/hydrochloric_acid_35_0_36_6_acs_...
They have a new director and recently some of their practices have been a bit shoddy! They have two main Brands Atom Scientific and ACP Pure, both use
exactly the same chems and both are from exactly the same building. But Atom Scientific is aimed at B2B and is double the price.
What annoys me is some chems like Chloroform they now only sell via Atom, its fairly cheap except. I placed an order for ACP pure over the phone, i
then asked for some Chloroform.
Despite it being delivered by the same company on the same day, they wouldnt include the shipping cost as one order! so they wanted £45 for the ACP
order (delivery) and another £45 for the Chloroform!! Despite the fact it would have been on the same van at the same time!! The ACP order also had
96% sulphuric acid in it amongst other Hazmat chems!
They have now lost a good customer! The shipping was more than the cost of 2.5ltr Chloroform.
I appreciate the input guys.
[Edited on 2-1-2018 by NEMO-Chemistry]
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unionised
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Because diluting concentrated HCl evolves heat.
Incidentally you can get a reasonable estimate of the density without a measuring cylinder.
Get a bottle and weigh it empty and then full of water- the difference gives you the volume.
If you then weigh it full of HCl solution (or whatever) you can find the weight of a known volume.
That lets you calculate the density.
[Edited on 2-1-18 by unionised]
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happyfooddance
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But why would you be pouring hot concentrated hydrochloric acid?
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unionised
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It doesn't need to be hot.
If you mix cold concentrated hydrochloric acid with water it gives out a little heat.
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NEMO-Chemistry
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see my post just above, it explains why and how he gave the info.
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NEMO-Chemistry
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| Quote: Originally posted by unionised |
Because diluting concentrated HCl evolves heat.
Incidentally you can get a reasonable estimate of the density without a measuring cylinder.
Get a bottle and weigh it empty and then full of water- the difference gives you the volume.
If you then weigh it full of HCl solution (or whatever) you can find the weight of a known volume.
That lets you calculate the density.
[Edited on 2-1-18 by unionised] |
I will get to use my hydrometers one day!!
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happyfooddance
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I see. But isn't that heat pretty negligible? I thought that the HCl in 32% is pretty much just as completely disassociated as it is in dilute
solution. I have a habit of stirring everything with a thermometer, and I have never noticed a temperature change diluting HCl acid.
Then again, with his new hi-accuracy thermometer set, he might!
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NEMO-Chemistry
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| Quote: Originally posted by happyfooddance | I see. But isn't that heat pretty negligible? I thought that the HCl in 32% is pretty much just as completely disassociated as it is in dilute
solution. I have a habit of stirring everything with a thermometer, and I have never noticed a temperature change diluting HCl acid.
Then again, with his new hi-accuracy thermometer set, he might! |
lol I used to stir with a thermometer......until a blob suddenly dropped to the bottom of the flask .
I got a couple of more accurate thermometers than those others from ebay, the lines are really close together though.
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aga
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His/her username is unionised not Unionised.
That's being pedantic 
Edit:
Yes, i know, a Capital observation, heigh ho.
[Edited on 2-1-2018 by aga]
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NEMO-Chemistry
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Yes and No, most people really hate it when there name is written wrong. Funny in a way as most of us dont use our real names...
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unionised
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Wrongly.
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