# Talk:PH

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 Definition:  A scale that measures the acidity or alkalinity of a solution, ranging from 0 (strongly acidic) to 14 (strongly alkaline). [d] [e]

## Article name

Is there anyway to get the initial p to be minuscule rather than capitalized (or should we just rename the article to Potential of hydrogen)? Wikipedia seems to use a {{lowercase}} template that we don't have. Benjamin Seghers 14:09, 9 October 2007 (CDT)

I've created a {{lowercase}} by simply copying the code from Wikipedia's same template. Not sure if it's allowed, but it worked. Benjamin Seghers 14:27, 9 October 2007 (CDT)

## the formula

The pH formula is wrong in reality, pH should be related to the activity (effective concentration) of hydrogen ions, but not just the concentration of hydrogen ions. However, I do not know how to modify the formula, can anyone correct this?--Wong Hung Kong Dylan 05:42, 3 June 2009 (UTC)

You are right, the pH formula is too simple-minded. It has the form that I (and probably many others) learned in high-school. As high-schools probably still teach it in this form, the formula has some (educational) use. --Paul Wormer 11:59, 3 June 2009 (UTC)

A fairly good description of pH, activity and the Nernst equation can be found at this site should anyone want to work on this article. David E. Volk 15:23, 10 June 2009 (UTC)

## typographical remark

Numbers do not need a "\mathrm". But O and H are symbols, not variables, and therefore should be \rm. Peter Schmitt 10:03, 4 June 2009 (UTC)

## missing definition/explanation

What does "[..]" stand for? Peter Schmitt 10:05, 4 June 2009 (UTC)

What do you mean? Where is "[..]"? and there is a definition... Caesar Schinas 10:17, 4 June 2009 (UTC)
 is used for concentration of OH-, but the precise meaning -- what number does it stand for? -- is not explained. Peter Schmitt 10:26, 4 June 2009 (UTC)
[H+] is the concentration of hydrogen ions in moles per litre of solution and [OH] is the concentration of hydroxide ions in moles per litre of solution. Milton Beychok 05:01, 10 February 2010 (UTC)

## Litmus paper only determines acidity or basicity

Peter, all that litmus paper does is determine whether the solution is acidic or basic. If the litmus paper turns red upon being wetted in the solution, the pH is less than 7 (acidic). If it turns blue, the pH is more than 7 (basic).

One can use a wide range of papers impregnated with different pH color idicators for pH values of 1 through 14.

However, the best way to measure pH is the use of pH meters consisting of two glass electrodes and a sensitive voltmeter calibrated to read in pH units. For a more complete explanation, see How does a pH meter work?.

This article needs a great deal of work . I don't think it deserves a status 2 at this time. In my opinion, it should be a status 3 (stub). Milton Beychok 04:03, 10 February 2010 (UTC)

Thank you, I did not doubt that there are more precise means to measure pH. I just added "litmus paper" because I thought it needs to be mentioned ... Concerning the status: I think that it is no longer a stub (it contains some basics), and that "developing" just means what you say: It "needs a great deal of work". But I will not argue either because I do not think that it matters much (except in the statistics). --Peter Schmitt 12:54, 10 February 2010 (UTC)

## Planning to revise this article quite a bit

I am going to to try my hand at rewriting this article in one of my sandboxes and then presenting it here. If at that time (within a week from now), anyone wants to add/delete/revise what I will have done, please feel free to do so. Milton Beychok 18:31, 10 February 2010 (UTC)

## Re-wrote the entire artcle

I have now re-written and re-formatted the entire article. Peter Schmitt, I am sure that you will want to check whether or not your recent copy edits are still needed. If so, please incorporate them.

This re-written version is still not a complete article. Sections that are still needed include:

• A section on the use of universal pH indicators along with charts of their colors.
• A discussion of the electrode method of measuring pH. This section should include a brief discussion of the Nernst equation for electrodes, using the Nernst equation as adapted for pH measurement. I used the word "brief" because I think the Nernst equation deserves a much more detailed, stand-alone article.
• A discussion of pH and how it is involved in chemical reaction equilibrium constants (Ka).

In general (in my opinion), this article should not have to include lengthy, detailed discussions of activity, activity coefficients, pH electrode meters or the Nernst equation. All of those should be stand-alone articles to which this article can link. All of those subjects should be only briefly discussed in this article (and some of them are already so mentioned in my re-written version).

Anyone that wants to edit what I have re-written, please feel free to do so. Milton Beychok 01:28, 15 February 2010 (UTC)

Paul Wormer has reviewed this article and made a number of revisions and corrections, all of which I agree with. Thanks, Paul. Milton Beychok 18:39, 28 February 2010 (UTC)

## to make pH a fully developed article

My idea on how to fully develop the pH article would be to include a short section on "pH measurement" including pH indicators or perhaps just a section on "pH indicators"; a section, perhaps even a short fundamental one, on "pH buffers"; and coverage of or at least mention of the Henderson-Hasselbalch equation with a link to its own article. Somewhere in CZ, there should be information on pH calculations but maybe in another article. Discussion of acid-base neutralization may appear in this pH article, or the Acid and Base (chemistry) articles. The Acid and Base (chemistry) articles still need to be significantly expanded. Acid and base equivalents and normalities would be covered there. Discussion of pH in titration curves can be mentioned in this article but covered in an Acid-base titration article. A general statement that many chemical species change structural form with changes in pH should be included in this pH article, perhaps giving the example of the chromate and dichromate equilibrium. It would be a good idea to have articles on Acid dissociation constant and Base dissociation constant in CZ covering these topics including pKa and pKb in more detail. The pH meter can be covered in detail in its own article. Henry A. Padleckas 08:11, 2 March 2011 (UTC)

Just go ahead and add whatever you think you should be included in this article. Also, just go ahead with whatever other related articles you think are needed. Milton Beychok 09:47, 2 March 2011 (UTC)