Back to Lew

Steve replied : Need to know the page that was written on.

Lew asked:
I've forgotten enough of my high school chemistry so tha I don't understand
Anchell's statement in one of the Cookbooks that a solution of NaOH and
water will have a short shelf life. Can anyone explain this?

I have a half filled, gallon jug of 50% that I use for a variety of
purposes. Is it time to throw this away?

-Lew




--
"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

greg_____photo(dot)com

Check out "The Darkroom Cookbook," 2ed, p.148. Solution B for formula #9 is
10g NaOH + 100ml H2O. First comment in the text that follows "Do not mix too
much of solution B, as it has a short shelf life."
-Lew
"G- Blank" wrote in message
...
Steve replied : Need to know the page that was written on.

Lew asked:
I've forgotten enough of my high school chemistry so tha I don't
understand
Anchell's statement in one of the Cookbooks that a solution of NaOH and
water will have a short shelf life. Can anyone explain this?

I have a half filled, gallon jug of 50% that I use for a variety of
purposes. Is it time to throw this away?

-Lew




--
"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

greg_____photo(dot)com

Check out "The Darkroom Cookbook," 2ed, p.148. Solution B for formula #9 is
10g NaOH + 100ml H2O. First comment in the text that follows "Do not mix too
much of solution B, as it has a short shelf life."
-Lew

In article ,
"Lew" wrote:

Check out "The Darkroom Cookbook," 2ed, p.148. Solution B for formula #9 is
10g NaOH + 100ml H2O. First comment in the text that follows "Do not mix too
much of solution B, as it has a short shelf life."
-Lew

Aha. I see the comment. First, both you and Mr. Lew need to understand, I
am not a chemist, I am a photographer who uses, and shares, formulas. The
formula is published as it was given to me by Maxim Muir. So, Mr. Lew has
two choices. He can either mix a small amount of hydroxide solution, as
recommended, or he can mix a whole bunch and take his chances. I think too
many photographers attempt to make something which should be relatively
simple into rocket science.


--
"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

greg_____photo(dot)com

Hi Greg:
My first name is Lew, I'm not Mr. Lew.
I wasn't asking about Muir's formula, my question was about the keeping
properties of NaOH in solution in general. This question was answered by
Michael Gudzinowicz in the original thread:

Dilute NaOH solutions absorb carbon dioxide from the atmosphere forming
carbonic acid which is converted to sodium carbonate in a NaOH solution,
neutralizing a small amount of NaOH. Carbonate is insoluble in a 40-50% NaOH
solution so the reaction is insignificant, and the solution has a long
storage life. In labs, NaOH is commonly used as a 50% w/w solution since it
is more stable than pellets, crystals or dilute solutions

-Lew