Talk:Solubility

A substance is soluble if it dissolves in a fluid.

I had never thought about gases being solvents but this implies that they can. Can the evaporation of water in air be described as solvation?

There are solid solutions, too. -- Heron

I found the following comment in the article. Maybe those who worked on this article like to see their work being helpful. andy 20:11, 11 Dec 2004 (UTC)

Your good, im taking honers physical science this year and this sight is a big help

thanks

The inorganic compound sodium hydroxide is at least partially soluble in alcohols. H Padleckas 23:07, 6 Apr 2005 (UTC)

I have removed the merge notice for solution and solvent and have modified the merge notice for soluble to reflect the consensus. Ancheta Wis 15:05, 3 September 2005 (UTC)Reply

Hi, I know that there should not be Hg₂²⁺ in this article, but what I don't know is whether it should be + or 2+, or if it matters. I thought I'd put up one of those annoying dispute notices and let someone else more knowledgable fix it... Thanks! -postglock 14:19, 27 November 2005 (UTC)Reply

No, that's correct, at least according to what I've been taught in school. I'd offer a quote if I could find it in my damn textbook, but no luck. I took the liberty of removing the notice--hopefully it won't offend. EvilStorm 18:12, 8 December 2005 (UTC)Reply

Oh ok... No, not offended at all. My chemistry is perhaps a little lacking, I didn't realise that you could get diatomic metal ions? I always thought they were monatomic (with the same element) or compound ions (with other elements)? -postglock 22:28, 8 December 2005 (UTC)Reply

I have improved the Soluble article to discuss solubility. That article also contains links to solute, solvent, and solution. H Padleckas 22:34, 6 Apr 2005 (UTC)

From the chart in the article, one could argue that NaCl (Common Table Salt) would be more soluble than Sucrose (Table Sugar) because of the fact that NaCl is ionically bonded and above the polar covalent bonds found in sucrose. However, many people seem to believe that the solubility of sucrose is greater than that of Sodium Chloride. Who is right? Is Sucrose more soluble, or is Sodium Chloride? 24.11.91.3 15:33, 3 April 2006 (UTC)Reply

I don't think that the chart is necessarily meant to imply that ionic compounds are always more soluble than polar covalent compounds, especially becasue the "metallic" bonding type is listed above polar covalent; most polar covalently bonded compounds are more soluble than metals. Natsirtguy 19:54, 4 October 2006 (UTC)Reply

Just an added note...your iron example is kind of confusing since iron can be soluble through siderophores, I don't know if that would matter too much since that is an exception

why the solubility increase when the temperature increase

Sometimes it does; sometimes it doesn't. --Smack (talk) 19:28, 29 December 2006 (UTC)Reply

why the solubility sometimes decrease when the temperature increase? according to my grade 9 science knowledge, it should be always increase, since molecules of water have higher chance to dissociate the ions ( or easier to form hydrogen bonds with polar covalent compounds). what makes that change? thanks Lichunhon (talk) 06:15, 27 June 2010 (UTC)Reply

Semi-hand-waving explanation here: At higher temperature, molecular mixtures tend to become more disordered (increasing T increases the importance of entropy term in the Gibbs free energy equation). The solvation you mention (water molecules forming hydrogen bonds or polar interactions with solvated molecules) is a form or order (those solvent molecules are specifically organized around specific solute positions). So at high temperature, it might be advantageous to disrupt that ordering, moving towards greater entropy. Less solvation->less solubility? The Real Truth is that it's all a balancing act: better to have ordered solid (not-dissolved/crystal) and disordered solvent, or have some solvent ordered around solvated stuff (dissolved)? The real answer obviously depends on the exact nature of a given solvent and solute, because the exact energetics of the solid and solvated forms. That graph in the Solubility#Factors affecting solubility section is kinda neat! DMacks (talk) 06:34, 27 June 2010 (UTC)Reply

I'm not sure, but couldn't solubility also be considered a physical property? -tcwd 23:23, 1 October 2006 (UTC)Reply

What are you refering to? Why is this relevant? JKW 21:42, 2 October 2006 (UTC)Reply

I think he's talking about the categories down the bottom, and feels that it should be added to the physical properties category also. Aquain (Non member) 06:05, 25 November 2006 (UTC)

He does have a point. Solubility is how much solute can dissolve in a solvent. Dissolvation is a physical property, so why not solubility? 17:08, 9 December 2006 (UTC)

okay, this page needs to be edited for sure, someone wrote " a solution at equilibrium that can kiss my butt" ^^^ LOL well..its changed for a while now...right?[BR] Well...are we gonna amerge Solid Solubility to this article? I'm not sure we should...we should just have a link to link to that article Invader05 00:34, 29 December 2006 (UTC)Reply

I'm not sure either. Does the term "solubility" usually include solid solutions? --Smack (talk) 19:28, 29 December 2006 (UTC)Reply

I noticed the absense of gas/gas solutions too. Maybe a mention of the atmosphere? —Preceding unsigned comment added by 208.201.160.2 (talk • contribs)

The situation of gases could be explained similarly using the words already written. It's just a matter of examples. --Deryck C. 06:47, 27 January 2007 (UTC)Reply

Moved from Wikipedia_talk:Chemistry_Collaboration_of_the_Month I tried to wade in to improve this article as the CCotM. It's quite a staggering task to perfect this article. I'd like to talk about it here before I do any damage, though. IMHO, a lot of the information simply doesn't belong in this article. Rather, they should be in the relevant related articles, such as solution, solvent, etc. Solubility should not attempt to encompass everything to do with this. Perhaps it should limit itself to

1. Definition (do we refer to the property of simply being able to dissolve, or the stricter definition (IUPAC) of the maximum amount of stuff which will dissolve?)
2. What determines a substance's solubility (briefly, main article being solution), including a passing mention of factors such as temperature and/or pressure (for the case of gases)
3. Applications of solubility in chemical processes, and everyday life e.g. making milk from powdered milk

Comments please! --Rifleman 82 16:52, 2 January 2007 (UTC)Reply

Yes, it's a challenging article, but a very important one. I think we need to address all of the above, and more. IMHO, we should address both definitions of the term, as given here. By the way, you might be interested to know the history of this page - it used to be called Soluble and was only changed a year ago. I suspect a lot remains to be cleaned up from that, though solubility is a much better title IMHO. I'd also like to reiterate my comments on the main page - we need to consider the related articles solvent and solution - that means not duplicating (or triplicating) a lot of information. As for other topics, I'd like to see a discussion of factors that make something soluble (or not), such as polarity and lattice energy. Should we move this discussion to Talk:Solubility to bring in a broader set of opinions? Walkerma 06:37, 3 January 2007 (UTC)Reply

I did a rewrite of much of the text, and added a more general chart showing solubility curves for a variety of salts - not just Na2SO4. I had trouble getting Excel to draw these curves, so I had to fill in the gaps with coloured pencil! Excel also won't let you have subscripts in the chemical formulae (even though my table had them). My poor artistic skills aren't too obvious unless you click on the image or look quite closely, but if anyone has better graphing software than Excel (or knows how to use Excel more effectively?), perhaps you could let me know and we could improve it. Another thing, I wanted to cover polarity under the "factors affecting solubility" since I thought it relevant, but then I found a section on organic compounds later on that sort-of covered much of the same topic. I tried to rewrite both to limit any duplication, but I'd appreciate a second pair of eyes on this. Maybe it's OK, but if not, feel free to consolidate if you think there is too much duplication. Thanks, Walkerma 07:14, 28 January 2007 (UTC)Reply

I managed to find out how to do this, so I cleaned it up. I may try to improve it more later. Walkerma 02:35, 17 February 2007 (UTC)Reply

The chart seems to put soluble and insoluble substances side by side. Not being a comparison chart, imo that's not a good presentation. An alternative chart puts the group of substances on either the soluble or insoluble side, and lists the exception on the other side. --Deryck C. 13:49, 17 January 2007 (UTC)Reply

Added hydroxide entry to table (see reference: Chemistry, Concepts and Problems). Otherwise the book reflects the same info but author(s) note the table is partial table and for use with the book material. — Preceding unsigned comment added by 70.177.172.35 (talk) 17:52, 3 June 2012 (UTC)Reply

hydroxides and oxides (except Group I, NH4+, Ba2+, Sr2+, Ca2+ and Tl+) Where CaO will react with water to form CaOH2 Solubility: 0.185g/100 cm³ Ksp = 4.68 × 10−6 That is misleading people that CaOH2 is soluble. I think we should change that. —The preceding unsigned comment was added by Snoopy11hk (talk • contribs) 09:18, 30 March 2007 (UTC).Reply

I undid this revision because it added rather extensive information that is essentially identical to that already contained in another section. The new information was added under section "Quantification of solubility" and it duplicates the content of "Solubility of ionic compounds in water". I apologize to the original contributor who obviously put a lot of work compiling the info independently. Stan J. Klimas 11:37, 23 September 2007 (UTC)

Could we probably turn that excess information into another article so as to preserve it? --Deryck C. 21:14, 20 April 2008 (UTC)Reply

Hi. Could someone draw a picture for this section. I think it would be VERY helpful for people to visually see how the different ions are attracted to each other. I WOULD draw it myself, but I don't have the software to make the chem-pictures. Anyone know if there's a free version somewhere?? —Preceding unsigned comment added by Armadillo1985 (talk • contribs) 01:50, 31 May 2008 (UTC)Reply

Hello. This seem to be more related to the article solvation. For free (open source) software, I would start with Category:Free_science_software. XDrawChem is perhaps the easiest to start with. Additional resources at http://www.redbrick.dcu.ie/~noel/linux4chemistry/ Stan J. Klimas (talk) 16:10, 31 May 2008 (UTC)Reply

• Is there a better title for the Molecular view section? I can't think of one but the title just doesn't seem that encyclopaedic. This section also needs 2-4 refs, preferably one for each separate paragraph.
• In general, I've tagged sections as opposed to statements with ^{[citation needed]}, but ideally each statement should be referenced.
• The term "ith" in the explanation of the Pressure equation is probably not well known to non-science/maths people, and may need an explanation in itself.
• I've removed the comment in the benzoic acid cynthesis: "On a practical note, the benzoic acid obtained after evaporating the organic solvent should ideally be purified by recrystallizing from hot water". Although it's correct it may be a bit confusing- perhaps there's a better (but still simple) example out there?

Cheers Freestyle-69 (talk) 23:02, 26 June 2008 (UTC)Reply

hjgfk —Preceding unsigned comment added by 76.232.157.129 (talk) 01:28, 23 October 2008 (UTC)Reply

The graphs relating Solubility and temperature are helpful, however they are lacking the temperature scale. (K, C, F) —Preceding unsigned comment added by 198.188.6.56 (talk) 21:21, 3 November 2009 (UTC)Reply

Seems to have been fixed at some point. DMacks (talk) 20:32, 22 July 2017 (UTC)Reply

Are gases most soluble at the top of a glass of water or at the bottom? In other words, is there a higher concentration of gas molecules at the top of an aqueous solution, or is there a higher concentration of gas molecules at the bottom? —Preceding unsigned comment added by 174.18.19.205 (talk) 17:38, 8 May 2010 (UTC)Reply

I actually got to the article via a redirect from slightly soluble - but the article doesn't discuss the various grades of solubility at all. I appreciate that increased traffic looks good for the page, but using a redirect that's mentioned nowhere on the page, and about which no information can be found, comes off very badly. It's akin to finding a search result purportedly about iguana breeding habits when it's actually a porn site ad. 76.22.25.102 (talk) 00:29, 30 May 2010 (UTC)Reply

The introductory sentence is: Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a liquid solvent to form a homogeneous solution of the solute in the solvent. Isn't the phrase homogeneous solution redundant? If it isn't homegeneous doesn't it become a heterogeneous mixture and not a solution?--PedroDaGr8 (talk) 23:37, 2 March 2011 (UTC)Reply

It's been a long time since frosh chem. I have a sense of how water dissolves polar molecules--the charge polarity of the molecule acts a little like a magnet, grabbing on to an exposed pole on the surface of the to-be-solute and pulls it off. (Let me know if that's off-base.) Then with nonpolar molecules, I can see why water wouldn't want to dissolve them--there'd be a surface energy at the interface because the water molecules like "dissolving" each other. But what about solubility. If I put individual molecules of ABS plastic in benzene, I can imagine that they would be happy together since the "outsides" of both molecules "look" like a bunch of covalently-bonded hydrogens, but how do nonpolar solvents pull their to-be-solutes apart? Obviously there's an energy gradient, but what is lower-energy about a plastic molecule in benzene versus one hanging out with its other plastic-molecule friends? Wouldn't there be an energy hump to get over to untangle the polymers? —Ben FrantzDale (talk) 14:08, 5 October 2011 (UTC)Reply

Hi. Hope I am doing this right. I am considered a bit of an expert in this field (I've published in it) - so I guess I shouldn't edit the actual page. This statement "The speed at which a solid dissolves may depend on its crystallinity or lack thereof in the case of amorphous solids and the surface area (crystallite size) and the presence of polymorphism.", is not strictly true. This is one of those cases where the lay term is used differently than the scientific term.

Baseline dissolution rates (the rate that a material dissolves) are already normalized to surface area. Therefore, all things considered equal, the rate of dissolution doesn't change depending on the surface area. Diss. Rates are in units of mol/m^2s. I think what is being talked about here is the rate of solubilization (sp?). Here's an example. A mass of a sugar with a surface area of one meter may go into solution in 1 unit of time. The same mass of a sugar with two meters of surface area will go into solution in 1/2 unit of time. I guess in lay terms you might say that one dissolves faster than the other. However, I think a more proper term is solubilizing because the dissolution rate is normalized to surface area and therefore (all things considered equal) doesn't change based on surface area. That said, changing the surface area can cause (or mitigate) reaction interface problems that can slow (or speed up) the effective dissolution rate. Large surface areas in unagitated solutions can effectively lock down the dissolution process because of saturation at the reaction interface - so even the lay use of the term isn't true. Also, there is a list of likely 50 different factors that impact effective dissolution rates - not simply xtalography

I'm not really sure how to word it to properly communicate it to a lay audience without running afoul of kinetics - or if that is even important to wikipedia. Prop Prospero66 (talk) 22:29, 14 December 2011 (UTC)Reply

To my understanding, experts are very much welcome in Wikipedia. So welcome to Wikipedia :)

It seems to me that the literature also defines the term "intrinsic dissolution rate", e.g., the U.S. Pharmacopeia] to avoid ambiguities.

Dissolution and solubilization have their own articles that can surely use expansion/improvements. The treatment of "dissolution" in the solubility article would best be focused on distinction between solubility and dissolution so that the two are not mixed up, in my opinion.

Best regards, Stan J. Klimas (talk) 00:11, 15 December 2011 (UTC)Reply

But it is not insoluable? A metal (M) and OH (hydroxide) MO will react with water to form a metal hydroxide M[(OH)2]. The metal oxide is a base, the metal hydroxide a new solute (the water is "consumed"). So a reaction does occur , so MO is certainly not "insoluable" but soluable and reacting.

(i see what you meant (when and how), but if it's included every subatomic fact in every label we cannot say anything without everything, making learning chemistry diffucult in deed)

— Preceding unsigned comment added by 70.177.172.35 (talk) 01:54, 4 June 2012 (UTC)Reply

I corrected the below (unfortunately lengthening it). Please talk if you think it needs help. What it should do is say that an application of solubility is equations and titration plus introduce terms, but very briefly, so that this is in mind for the reader who reads sections following Applications.

Solubility and insolubility together indicate whether solubility reactions will take place. This can be read from a correctly written balanced chemical equation (complete ionic notation) by noting whether any products are formed from the soluble reactants. If reactants in solvent form a precipitate, covalent compound, water, a weak electrolyte, a gas or water (aq) then a reaction takes place, otherwise not (they are all spectator ions). An example: if bubbles are seen a gas was produced, a re-bonding reaction occured. [16]

I removed this paragraph from the article again because it has multiple inaccuracies. The sentence "Solubility and insolubility together indicate whether solubility reactions will take place" is vague and its meaning is not clear at all. The second sentence "This can be read from a correctly written balanced chemical equation (complete ionic notation) by noting whether any products are formed from the soluble reactants" doesn't make any sense to me because in any balanced chemical equation there are reaction products. Also, the phrase "This can be read" is simply ambiguous. It is not true as a general rule that "If reactants in solvent form a precipitate, covalent compound, water, a weak electrolyte, a gas or water (aq) then a reaction takes place" because it there are many exceptions - it ignores activation energy, rates of reaction, and the dependence on factors such as temperature. The claim that "if bubbles are seen a gas was produced, a re-bonding reaction occured", in additional to being grammatically incorrect, is also not true as a general statement because there can be other reasons for the production of gas such as boiling of the solvent, to name one. -- Ed (Edgar181) 12:56, 4 June 2012 (UTC)Reply

It would be wonderful to have someone write a cogent explanation of the standard reporting terms for solubility and the variants that exist in the literature. Thus, one might consider practical preparations (35g sodium chloride added to 100 g water), measured amounts (100 g of a sample is evaporated to produce 3 g sodium chloride, thus is a 3 wt% solution of sodium chlroride). What about PPM - does this constitute the first case or the second?? — Preceding unsigned comment added by 131.167.254.100 (talk) 16:15, 14 November 2012 (UTC)Reply

I agree. It would be nice with either g/100 ml or wt% as a standard. In the formaldehyde article the solubility is given in g/dm-3... that is just more confusing to the reader than useful. One could at least write g/l, it's not like we need to glorify the SI-units by entangling our data. OxygenBlue (talk) 09:05, 21 January 2013 (UTC)Reply

The terminology is very confusing. Sometimes, it seems to be the amount of solute in the amount of solvent before the solute is added to it. Other times, it seems to be the amount of solute in a fixed quantity of the final solution. For example, the solubility of sodium chloride is claimed to be 359 grams per litre. Is that 359 grams of sodium chloride into one litre of pure water ? Or 359 grams of sodium chloride in one litre of the resulting solution ? But if you go on and read about mixtures of alcohol and water, it seems to be quite different. Lathamibird (talk) 05:36, 20 February 2016 (UTC)Reply

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I came to this article to find out how solubility is determined empirically, but I'm none the wiser.Ttocserp 16:02, 6 March 2017 (UTC)

The source for a definition of "insoluble" as < 0.1 g per 100 ml - Rogers, Elizabeth; Stovall, Iris (2000). "Fundamentals of Chemistry: Solubility". Department of Chemistry. University of Wisconsin. Retrieved 22 April 2015 - leads to a 403 Forbidden error. Either an equivalent source should be found or the claim should be removed. Gsurfer04 (talk) 13:55, 11 May 2017 (UTC)Reply

This edit request has been answered. Set the |answered= or |ans= parameter to no to reactivate your request.

change ((salt))s to ((Salt (chemistry)|salts)) — Preceding unsigned comment added by 73.154.31.58 (talk • contribs) 12 May 2017 (UTC)

  Done. I did not change the wikilink in the "Solubility of ionic compounds in water" section since salts is a redirect to Salt (chemistry). —KuyaBriBri^Talk 21:24, 12 May 2017 (UTC)Reply

I can't believe I didn't find this information in Wikipedia article.

https://www.sigmaaldrich.com/united-kingdom/technical-services/solubility.html

Approx Volume (ml) of Solvent Needed to Dissolve 1g of Solute

• Very Soluble, Less than 1
• Freely Soluble, 1 to 10
• Soluble, 10 to 30
• Sparingly Soluble, 30 to 100
• Slightly Soluble, 100 to 1000
• Very Slightly Soluble, 1000 to 10,000
• Practically Insoluble, Greater than 10,000

ee1518 (talk) 16:09, 18 January 2018 (UTC)Reply

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I wish to add that mass and volume also help to determine the solubility of a substance. The higher the level of solute, different solutions such as unsaturated, saturated, and supersaturated can be formed by utilizing different techniques to achieve this. Treeman183 (talk) 15:30, 27 October 2019 (UTC)Reply

Mass & Volume already appear in some places within the article. If you would like to request a specific change, you'll need to be specific: "the request must be of the form "please change X to Y"." - ChrisWar666 (talk) 19:26, 27 October 2019 (UTC)Reply

This article should include info re the solubility of substances in mixed solvents.--109.166.137.83 (talk) 23:30, 19 July 2020 (UTC)Reply

This seems way too specific to link in "See Also" and there is no explanation as to why it's there. Should we not be linking to more general subjects related to solubility prediction such as Molecular modelling? Gsurfer04 (talk) 16:35, 25 January 2021 (UTC)Reply