From: Pay (payral@club-internet.fr)
Date: 02/19/03-12:09:35 PM Z
What percentage citric acid solution do you use as starting one ?
Richard Sullivan a *crit :
>
> Yes,
>
> Philippe is correct.
>
> I might also add that ammonium citrate is strongly buffered and this might
> cause some confusion when making it.
>
> What happens is as you add ammonia the pH will gradually go up step by step
> more or less linearly to the amount of ammonia being added. When you get to
> 6.5 it will stop moving and at that point you can add a quite a quantity of
> ammonia without seeing a move in the pH and then suddenly the pH will start
> to move up again. It's a slope up, a flat spot and a slop up. As most paper
> will be alkaline today it is best as Philippe says to be on the acid side
> of the buffer point. Ammonium citrate is nice in this regard as it holds it
> pH pretty steady due to the buffer action. Philippe has a far more
> knowledge of chemistry than I do so if I've not explained this quite right
> my apologies.
>
> --Dick Sullivan
>
-- Ayral Philippe 52, rue de Vallard 74240 Gaillard France Tél/Fax: +33 (0)450 39 79 81 http://perso.club-internet.fr/payral http://www.focale.ch
This archive was generated by hypermail 2.1.5 : 03/04/03-09:19:09 AM Z CST