Talk:Phenolphthalein

message: This page is badly formatted in MSIE, and I have no idea how to correct the "colorless" bit in the box for MSIE and Opera. It works in Firefox, but the long vertical image causes problems there.. 218.102.71.159 10:47, 28 November 2005 (UTC)
thread_title: Comments

message: Why is the melting point listed as higher than the boiling point? —The preceding unsigned comment was added by 74.64.65.118 (talk) 16:40, 18 February 2007 (UTC)
thread_title:  Error! 

message: Does anyone know exactly what this is (i.e. the form present below pH 0) - as it leaves rather a hole in the article. 86.148.60.205 19:54, 2 March 2007 (UTC)
replies: text:  See below in Talk:Phenolphthalein#Forms. It is still a complicated matter. --Taweetham (talk) 05:15, 19 June 2020 (UTC)
thread_title:  Structure for In 

message: A quick note (this is not really article material): James Outlaw, PhD (a chemistry professor I know) tells me that there are two reasons for keeping the indicator (phenolphthalein) present all of their labs' pure ethanol. First, it is handy to have so you aren't required to add it later for any acid/base titration. However, the second reason is related to its medical uses. By adding the indicator to otherwise pure drinking alcohol, the ethanol is rendered undesirable to drink, as the phenolphthalein would cause severe diarrhea. Josh3580 14:31, 5 March 2007 (UTC)
thread_title: Laxative Use

message: I know phenolphthalein is used in construction materials testing (for roadways especially), to test for the presence of stabilizing agents in soils, such as lime, cement, or fly-ash, because it picks up the presence of Calcium ions or CaO, or something similar.  However, i'm not familiar with the chemistry of it, can someone more knowledgeable add it to the 'uses' section in the article?Foij00 21:06, 11 May 2007 (UTC)
thread_title: Uses - Construction

message: Error!
Why is the melting point listed as higher than the boiling point? —The preceding unsigned comment was added by 74.64.65.118 (talk) 16:40, 18 February 2007 (UTC)
thread_title:  Response to Error! 

message: What is the pronuncation for phenolphthalein? --139.103.73.75 23:23, 8 November 2007 (UTC)
thread_title:  Pronunciation 

message: What is the pH of phenolphthalein? 72.67.175.145 (talk) 07:14, 13 December 2007 (UTC)
thread_title:  pH 

message: This article has contradictions. 
The orange in acid is contradictory to the text, or if not needs further explanation.  —Preceding unsigned comment added by 80.176.155.189 (talk) 22:31, 2 January 2008 (UTC)
replies: text:  See below in Talk:Phenolphthalein#Forms. It is still a complicated matter. --Taweetham (talk) 05:17, 19 June 2020 (UTC)
thread_title:  Contradictory 

message: I believe that the colour phenolphthalein turns in an acidic solution is COLOURLESS not orange and in a neutral solution a pink tinge and in alkaline pink. Is this correct? Several other websites back this up as does my chemistry teacher and a practical OCR chemistry paper. Please could someone infrom me if this is correct as i did not want to change the infomation on the page straight away. Many Thanks.  —Preceding unsigned comment added by AdamJKB (talk • contribs) 11:48, 9 May 2008 (UTC)
replies: text: Phenolphthalein does indeed turn orange in very strong acid solutions (hydronium > 10M). Have a chemistry teacher put some full strength sulfuric acid in a small beaker (do this in a fume hood), and add a few drops of the indicator. It will turn orange. — ★Parsa ☞ talk 21:53, 1 May 2013 (UTC)
thread_title:  Error concerning colour in acidic and alkaline solutions 

message: the ph of pkenolphthalein is between 8.2 to 10.0  —Preceding unsigned comment added by 59.93.240.6 (talk) 14:31, 14 August 2009 (UTC)
replies: text: I'm assumming you mean phenolphthalein. Phenolphthalein is an indicator for pH. The color will transition from clear to fuchsia (magenta) over a range of about 8.0–9.6. In solutions with pH above about 10, the indicator will turn the solution magenta. In solutions below about 8 (which includes all acids and neutral solutions), the solution will remain clear. In full strength strong acids the color will change to orange. — ★Parsa ☞ talk 22:00, 1 May 2013 (UTC)
thread_title:  ph 

message: Can someone who knows plaese add a synthesis section? We usually have them, especially for rather important compounds such as this. Msaunier (talk) 07:45, 4 August 2011 (UTC)
thread_title:  Synthesis 

message: A section should be added that details phenolphthalein allergies and its manifestations.
72.82.166.184 (talk) 03:21, 2 February 2014 (UTC)
thread_title:  Allergy 

message: In the intro it says 'Phenolphthalein is insoluble in water and usually is dissolved in alcohols for use in experiments'. Then in the chembox we have the property 'Solubility in water : Soluble'. Which is correct? Plarstic (talk) 14:05, 10 February 2015 (UTC)
thread_title:  Contradiction 

message: Hello fellow Wikipedians,
I have just added archive links to  on Phenolphthalein. Please take a moment to review my edit. If necessary, add  after the link to keep me from modifying it. Alternatively, you can add  to keep me off the page altogether. I made the following changes:
*Added archive https://web.archive.org/20060925035727/http://www.iscid.org/encyclopedia/Universal_Indicator to http://www.iscid.org/encyclopedia/Universal_Indicator
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thread_title:  External links modified 

message: Substituted at 02:49, 30 April 2016 (UTC)
replies: text: pH isn't percent-acidity. The simple definition is pH=-log([H+], so pH=0 means [H+] is 1 M, an easy solution to make. Commercial hhydrochloric acid is about 12&mbsp;M and commercial sulfuric acid is about 18 M. There is a leveling or activity-coefficient effect to consider (see our pH article for details) but it's still easy to go beyond the "intro-level textbook definition" of 0–14. DMacks (talk) 11:37, 25 April 2020 (UTC)
thread_title: Assessment comment

message: Its twice stated (in parentheses:"(hence the name)") that its name comes from the acidic conditions during the syntheses. I do not get that. What part in the name is hinting to acidic conditions? -ein?? why??? --193.154.115.241 (talk) 03:56, 3 December 2017 (UTC)
thread_title:  Hence the name 

message: Why does this article have a redirect from "Feen-A-Mint gum"? Shouldn't the product be mentioned somewhere in the article to justify a redirect? Eddie Blick (talk) 22:12, 14 December 2018 (UTC)
replies: text: I added a detail mentioning it. DMacks (talk) 11:29, 25 April 2020 (UTC)
replies: text: , Thanks! Eddie Blick (talk) 13:15, 25 April 2020 (UTC)
thread_title:  Feen-a-mint gum 

message: To get six forms, you will need Ph5 and Ph6 in  which have sulfate group in the structure.  I am wondering if this is appropriate in the context of a pH indicator.  --Taweetham (talk) 10:39, 25 April 2020 (UTC)
replies: text: Good point! If it's a color-change that is in response to pH and sulfate, it's not strictly as a pH indicator. I adjusted the sentence. However, There is still an unstated mono-anionic form. I'd wondered why we don't have HIn– listed, which seems like an obvious intermediate in the H2In → In2– process. It is one of the structures in the animation later in the article. Apparently it is also colorless just like H2In. And there is another colorless form that can exist in the same low-pH as the H2In structure: hydrolysis of the lactone. And there is another colorless isomer of HIn– in equilibrium with the given one. None of these represent useful additions to the color-change intervals of this table. See doi:10.1007/s10847-008-9419-3 and doi:10.1007/PL00013491 for structures. DMacks (talk) 11:14, 25 April 2020 (UTC)
replies: text:  Totally agree for the HIn– point.  I feel that the information as written is dodgy in several ways but so far I only find two papers to help patch some parts. Personally, I do not like the animation there but let start by fixing the reaction scheme and see if the animation is still valid. Let me summarize the state of the article and the two references you gave in the table below so that we are on the same page.--Taweetham (talk) 02:13, 26 April 2020 (UTC)

text:   I revised to the article as my student and I found new references with pKas values of the dye and its sulfonated derivative. I leave the details for my students to fill later but made the structural changes myself.--Taweetham (talk) 07:11, 23 February 2022 (UTC)
thread_title:  Forms 

message: This page should have an IPA transcription, because this word hard has a pronunciation that is very different from how it's spelled. I transcribed it here so no one else has to do it: /ˌfinəlˈθælin/.  Sultan the Sultan (talk) 06:31, 21 April 2022 (UTC)
replies: text: I agree. However it depends on accent. The British pronunciation is /ˌfinɒlˈθεɪlin/ or alternatively /ˌfinɒlˈfθεɪlin/. Some people say the /fi/ as /fε/, and some people say the /εɪ/ as /æ/ or /ɑ/. GamerAJ1025 (talk) 15:29, 19 January 2024 (UTC)
replies: text: Americans will likely say /ˌfinɑlˈθεɪlin/ or /ˌfinɑlˈθeɪlin/ GamerAJ1025 (talk) 15:31, 19 January 2024 (UTC)
thread_title:  Add IPA