[pure-silver] Re: Hypo Clearing: citric acid or sodium citrate?


John,
More than a slight effect on pH. Solutions of citric acid are acidic, whereas solutions of sodium citrate are alkaline (salt of a weak acid). My guess is that if citric acid is added to hypo clear, it is done for pH control, in which case sodium citrate is not an acceptable substitute.
Bisulfite and sulfite form a buffer, but if the citric acid concentration is high, the buffer system can easily be overwhelmed. (Buffers have a fixed capacity.) 

Jordan

john stockdale wrote:
Forgive me if I've been inattentive, but is it citric acid or sodium citrate that's added to hypo clear? I seem to have references to both. Or doesn't it make much difference? Citric acid is very easy to obtain.
My schoolboy chemistry suggests that either becomes citrate ions in solution and the rest of it (sodium ions or H+) might have a slight effect on the pH and nothing more. And if the sulphite + metabisulphite forms a buffered solution then the effect on pH would be insignificant.
Can someone confirm or correct me?============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there. 

--


Jordan Wosnick
jwosnick@xxxxxxxxxxx

=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your 
account (the same e-mail address and password you set-up when you subscribed,) 
and unsubscribe from there.

Other related posts: