Wikidata:Property proposal/pH

pH value

Originally proposed at Wikidata:Property proposal/Natural science

Done: pH value (P9440) (Talk and documentation)

Description	property to indicate the acidity and alkalinity of an aqueous solution
Represents	pH (Q40936)
Data type	Quantity
Domain	items about aqueous solutions writ large, including fluids inside and around organisms, food, technical systems or locations
Example 1	distilled water (Q274959) → 7
Example 2	Camembert (Q131480) → 7.44 (according to Over two thousand estimations of the pH of representative foods (Q106003872))
Example 3	maple syrup (Q402563) → 5.15 (according to Over two thousand estimations of the pH of representative foods (Q106003872))
Example 4	Edam (Q597473) → 5.40 (according to Over two thousand estimations of the pH of representative foods (Q106003872))
Expected completeness	always incomplete (Q21873886)
See also	pKa (P1117), temperature (P2076), salinity (P4350), serving temperature (P7767)
Wikidata project	WikiProject Chemistry (Q8487234)

Motivation

The pH (Q40936) is a basic parameter used to characterize essentially any chemical system containing hydronium (Q849881), from food to bodily fluids to lakes, cosmetics and batteries, cell cultures and beyond. In many cases, the value is rather a range that depends on circumstances (e.g. whether a vegetable was raw or cooked, or how long a cheese has had time to ripen), so we probably need to think about how to indicate such things via suitable qualifiers and/ or dedicated items. Daniel Mietchen (talk) 03:40, 7 April 2021 (UTC)[reply]

Discussion

Notified participants of WikiProject Chemistry --Daniel Mietchen (talk) 03:45, 7 April 2021 (UTC)[reply]

Can you clarify how you envision this relates to acid dissociation constant (Q325519) with pKa (P1117)? --Egon Willighagen (talk) 07:15, 7 April 2021 (UTC)[reply]

I think this would be more like a property on mixtures like food not pure substances. In that case weak

Support from me. --SCIdude (talk) 07:52, 7 April 2021 (UTC)[reply]

Yes, what I have in mind here in terms of usage for this pH property is more about mixtures, not pure substances. Acidity of things like food, bodily fluids or lakes is commonly expressed in terms of pH, not pKa. I have added pKa (P1117) under "See also", though. --Daniel Mietchen (talk) 14:41, 7 April 2021 (UTC)[reply]

Support Thanks for the clarification. A clear notion that it should not be use for chemical compounds would be most welcome. --Egon Willighagen (talk) 17:08, 8 April 2021 (UTC)[reply]

Strong

Support from me. it's only distantly related to pKa . It's the concentration of hydrogen ions in a substance (necessarily a collection of many molecules, not necessarily identical). It's closely related to solutions, and I have raised this in Wikiproject:Chemistry but no replies yet Petermr (talk) 16:44, 7 April 2021 (UTC)[reply]

Support ArthurPSmith (talk) 17:20, 7 April 2021 (UTC)[reply]

Support, an important property for chemistry.--Arbnos (talk) 22:37, 12 April 2021 (UTC)[reply]
Done @Daniel Mietchen, SCIdude, ArthurPSmith, Arbnos, Petermr: please help complete the property and make good use of it. --- Jura 16:01, 14 April 2021 (UTC)[reply]