pH of 35.2 wt % HCl?
pH of 35.2 wt % HCl?
(OP)
Hi guys. Mech engr here, in over my head again, as usual. How do I estimate the pH of a 35.2 weight % HCl solution? Is this acid too strong to use the old pH = -log[H+] and I have to take the log of the activity (which I have no idea how to do)?
Thanks guys! Pete
Thanks guys! Pete
RE: pH of 35.2 wt % HCl?
HCL
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: pH of 35.2 wt % HCl?
RE: pH of 35.2 wt % HCl?
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: pH of 35.2 wt % HCl?
Source: http://antoine.frostburg.edu/chem/senese/101/acidb...
RE: pH of 35.2 wt % HCl?
http://www.cleartech.ca/ckfinder/userfiles/files/H...
Negative pH values may be possible, but would be unusual in practice. There are some complications in high molarity acid solutions that make pH calculations from acid molarity inaccurate and difficult to verify experimentally:
Even strong acids don't dissociate completely at high concentrations. Some of the hydrogen remains bound to the chlorine, making the pH higher than you'd expect from the acid molarity.
Because there are so few waters per acid formula unit, the influence of hydrogen ions in the solution is enhanced. We say that the effective concentration of hydrogen ions (or the activity) is much higher than the actual concentration. The usual general chemistry text definition of pH as -log [H+] (negative the logarithm of the hydrogen ion molarity) is better written as pH = - log aH+ (negative the logarithm of the hydrogen ion activity). This effect is very strong, and makes the pH much lower than you'd expect from the acid molarity.
If you were to dip a glass pH electrode into the 12 M HCl solution to actually measure the pH, you would get a pH that was higher than the true pH. This well-known defect in glass pH electrode measurements is called the "acid error"; it is sensitive to experimental conditions and difficult to correct for.