RE: Normal solution
|From:||Jim at ProSciTech <firstname.lastname@example.org>|
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
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.
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On Thursday, March 01, 2001 8:00 AM, Lott, Robert [SMTP:Robert.Lott@bhsala.com]
> 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:firstname.lastname@example.org]
> 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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