Talk:pH

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Negative pH[edit]

I see that this semi-protected article has a sentence in the lede: Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively (with a reference to an Journal of Chemical Education article). This sentence is not further detailed in the content sections and thus the issue of negative pH significance is left in suspension. Some explaining sentences would be useful. (This is also intended as semi-protected edit request).--5.2.200.163 (talk) 11:36, 4 July 2018 (UTC)

I'll just leave this here, if someone wants to add detail from it. The referenced entry in the journal includes: "For example, commercially available concentrated HCl solution (37% by mass) has pH ≈ –1.1, while saturated NaOH solution has pH ≈15.0 (22). Hot springs near Ebeko volcano, with naturally occurring HCl and H2SO4, have estimated pH values as low as –1.7 (23, 24). Waters from the Richmond Mine at Iron Mountain, CA, have pH = -3.6 (25, 26)"; the citations being:
  • (22) Dickerson, R. E.; Gray, H. B.; Darensbourg, M. Y. Chemical Principles, 4th ed.; Benjamin Cummings: Menlo Park, CA, 1984
  • (23) Ivanov, V. V. Geokhimiya 1955, 1, 63.
  • (24) Nikitina, L. P. Presented at Proceedings of the Water-Rock In-teraction Symposium, Prague, Czechoslovakia, 1974.
  • (25) Nordstrom, D. K.; Alpers, C. N. Proc. Natl. Acad. Sci. U.S.A. 1999, 96, 3455.
  • (26) Nordstrom, D. K.; Alpers, C. N.; Ptacek, C. J.; Blowes, D.W. Environ. Sci. Technol. 2000, 34, 254.
--Inops (talk) 14:26, 10 August 2018 (UTC)


I was surprised to see the reference to "popular belief". I have never heard of any such restriction to between 0 and 14. That would be saying the H+ concentration cannot go over 1M or under 10-14 M. Eaberry (talk) 05:21, 25 October 2018 (UTC)

Do you think there should be something about OH- (hydroxide) ions in the main blurb?[edit]

I'm not an expert in chemistry specifically but it is very tangential to my field... this youtube video gives a very clear and concise explanation, assuming its not oversimplified or wrong...? https://www.youtube.com/watch?v=E7qXfON0yG8

Should this content in written form be perhaps included in the main blurb? — Preceding unsigned comment added by 50.102.78.63 (talk) 13:41, 27 May 2020 (UTC)

I do think this need to be in there. In fact the opening paragraph that describes pH as the concentration of hydrogen ions is just plain wrong. The pH scale is based on the ratio of protons(H+ not H-) to hydroxide ions. The same ratio can be achieved at very high or very low concentration and the pH will remain the same. — Preceding unsigned comment added by 73.193.32.170 (talk) 04:47, 11 July 2020 (UTC)

Semi-protected edit request on 17 October 2019[edit]

Please provide a quantitative estimate for the difference between the total and seawater pH scales (in seawater). To do that, change "very small" to "very small (about 0.01)". I am a marine chemist specialized in the carbon cycle. OAguy (talk) 16:56, 17 October 2019 (UTC)

 Not done: please provide reliable sources that support the change you want to be made. Unfortunately, personal knowledge isn't sufficient. The information needs to be verifiable in a reliable, published source. See also Wikipedia's policy on original research. ‑‑ElHef (Meep?) 18:02, 17 October 2019 (UTC)

pH indicators[edit]

I think the main article that is linked to by the pH indicators section needs to be pH indicator not Universal indicator since there are many pH indicators and universal indicator is just one. Jasoninkid (talk) 22:41, 12 June 2020 (UTC)

Seems reasonable. Done.  Velella  Velella Talk   22:50, 12 June 2020 (UTC)
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