RE: Normal solution
From: | Jim at ProSciTech <jim@proscitech.com> |
Some people may not be aware that a strong stock solution can be diluted
whatever is required. So 2.0 N diluted 1+ 9 (H20) becomes a 0.2N solution. A 10
N solution of NaOH (near saturated)lasts indefinitely, whereas a 1N solution
contaminates with carbonates in time.
When making up NaOH solutions, a couple of other bits of lab practice should be
remembered:
The reaction is strongly exothermic and the temptation to make the solution up
in a volumetric glass flask should be resisted, since they tend to crack. Weigh
the pellets into a conical flask, they can stand the heat better. Then add most
of the water required and dissolve, perhaps with the aid of a stirring bar.
After the solution is cooled transfer into a volumetric flask and make up to
the exact quantity required.
Long term storage should be in a strong plastic bottle since concentrated
caustic attacks glass.
For some applications its important to have a carbonate free solution of NaOH
(certainly for lead staining in electron microscopy), this requires some
additional precautions, but that is another topic.
Cheers
Jim Darley
ProSciTech Microscopy PLUS
PO Box 111, Thuringowa QLD 4817 Australia
Ph +61 7 4774 0370 Fax:+61 7 4789 2313 service@proscitech.com
Great microscopy catalogue, 500 Links, MSDS, User Notes
ABN: 99 724 136 560 www.proscitech.com
On Thursday, March 01, 2001 8:00 AM, Lott, Robert [SMTP:Robert.Lott@bhsala.com]
wrote:
> A 2N solution of NaOH contains two gram-equivalent weights of solute per
> liter of solution. To determine the gram equiv. weight of NaOH, you simply
> add the molecular weights of Sodium-23, Oxygen-16, and Hydrogen-1 = 40.0
>
> 40.0 gm/1000.0 ml d-water = 1N
> 80.0 gm/1000.0 ml d-water = 2N
> 200.0 gm/1000.0 ml d-water = 5N
>
> -----Original Message-----
> From: Laurie Colbert [mailto:laurie.colbert@schs.com]
> Sent: Wednesday, February 28, 2001 1:13 PM
> To: Histonet
> Subject: Normal solution
>
>
> Help! Can someone tell me exactly how to make a 2N and a 5N solution of
> sodium hydroxide?
>
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