I've read in several places (edit: 1, 2, 3, 4, 5, 6, 7, 8. 9, 10, 11, 12) that there are many practical factors that make accurate pH measurements of roughly neutral environmental water samples more challenging than significantly basic or acidic samples.
Since the glass probes are sensitive fairly specifically to hydrogen or hydronium activity, why would concentrations around $\ce10^{-7}$ be more challenging than a much higher or especially much lower concentration, say $\ce10^{-10}$?
Discussions of the problem seem to center around issues related "solutions of low ionic strength", so a basic solution near pH 10 and a buffered solution near ph 7 would both have less practical measurement issues than a non-ionic solution near pH 7.
Is there a way to explain the practical issues clearly, but in fairly simple, somewhat physical rather than purely mathematical terms?
No comments:
Post a Comment