katchum - 15-11-2006 at 15:04
Hi
I have some difficulty in understanding this:
Suppose I have a feed NaOH solution 20%. This solution has a high pH. Maybe pH 10 (haven't calculated it) Now I add some HCl gas through the solution.
The pH drops to a level. Suppose that level is high enough to make an irreversibel reaction between HCl and NaOH. Like pH = 8.
If I keep the pH at this same level, by recycling the liquid to the feed. How much HCl can I absorb in this liquid at equilibrium?
Maybe my question isn't right, well I don't understand it...
[Edited on 15-11-2006 by katchum]
Nerro - 15-11-2006 at 15:47
The pH of NaOH 20% =~ 13.7 
The reaction is "irreversible" untill you reach pH 7 at which point all the NaOH has been used up.
I'm not sure if this helps you though I dont really understand your question...
Maya - 15-11-2006 at 17:03
The amount of HCl that this system cam absorb at equilibrium is equal to the total amount of NaOH in your system ( Conc. NaOH X Volume Liquid ) Plus
32% or so the weight of the water solution , aproximately. the pH will be extremely acidic. Unless you want pH 7-8, then max is the naoh conc x liquid
volume
really you can't recycle the feed b/c once it is used, in a closed system, it is used. are you talking an open system???