Homebrew PCBs

DJ Delorie wrote:
> 
> 
> 
> My current question is about pH or HCl molarity. Adam Seychell's page
> says that pH strips won't work because the copper messes up the
> reading. What about the cheap digital pool pH meters? They claim
> they support 0-14, but (1) will the copper mess those up? and (2) how
> does the molarity translate to pH in a CuCl solution?

pH is nothing more than a logarithmic scale of hydrogen ion activity. 
Some of your HCl will be exists as HCl molecules while the remainder 
dissociates as hydrogen ions and chloride ions. To further mess up pH, 
not all of these hydrogen ions are active at such high concentrations. 
Since pH only responds to active hydrogen ions you will get a false low 
acid reading.

At very low HCl concentrations < 0.01 molar then the pH begins to gives 
better indication of HCl concentration.