Solubility Definition and 25 Discussions

Solubility is the property of a solid, liquid or gaseous chemical substance called solute to dissolve in a solid, liquid or gaseous solvent. The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure and presence of other chemicals (including changes to the pH) of the solution. The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute.
Insolubility is the inability to dissolve in a solid, liquid or gaseous solvent.
Most often, the solvent is a liquid, which can be a pure substance or a mixture. One may also speak of solid solution, but rarely of solution in a gas (see vapor–liquid equilibrium instead).
Under certain conditions, the equilibrium solubility can be exceeded to give a so-called supersaturated solution, which is metastable. Metastability of crystals can also lead to apparent differences in the amount of a chemical that dissolves depending on its crystalline form or particle size. A supersaturated solution generally crystallises when 'seed' crystals are introduced and rapid equilibration occurs. Phenylsalicylate is one such simple observable substance when fully melted and then cooled below its fusion point.
Solubility is not to be confused with the ability to dissolve a substance, because the solution might also occur because of a chemical reaction. For example, zinc dissolves (with effervescence) in hydrochloric acid as a result of a chemical reaction releasing hydrogen gas in a displacement reaction. The zinc ions are soluble in the acid.
The solubility of a substance is an entirely different property from the rate of solution, which is how fast it dissolves. The smaller a particle is, the faster it dissolves although there are many factors to add to this generalization.
Crucially, solubility applies to all areas of chemistry, geochemistry, inorganic, physical, organic and biochemistry. In all cases it will depend on the physical conditions (temperature, pressure and concentration) and the enthalpy and entropy directly relating to the solvents and solutes concerned. By far the most common solvent in chemistry is water which is a solvent for most ionic compounds as well as a wide range of organic substances. This is a crucial factor in acidity and alkalinity and much environmental and geochemical work.

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  1. S

    Chemistry Is this the right way to approach solubility problem?

    Is my work and the answer correct? If not, how should I approach this problem? Thank you!
  2. M

    Chemistry Molar solubility lab questions

    I’m confused on how to calculate molar solubility because I don’t see what’s the difference between that and Ksp.
  3. K

    Solubility calculations

    Hello, I am a bit confused re. solubility calculations. Calculate the solubility of Pb(OH)2 at pH 10. Setting up the expression for Ksp: Ksp = [Pb2+][OH-]2 = 8* 10^-17 (Ksp value from SI chemical data) pOH = 14 - 10 = 4, i.e. [OH-] = 10-4. 8*10-17 = [Pb2+][OH-]2. Solving for [Pb2+] we get...
  4. J

    Determining Solubility in Acidic Solutions / Pure Water

    Homework Statement How many of the following would you NOT expect to be more soluble in acid than in pure water? FeS, CuCN, AlPO4, BaCO3, AgCl Homework Equations None necessary The Attempt at a Solution So we know that anything with OH- or anything that has the conjugate base of a weak acid...
  5. Z

    Carbon dioxide in liquid and gaseous phases with liquid water

    What are the differences between carbon dioxide solubility (miscibility, reaction) in liquid water when in gaseous (<38 bar) and liquid (>38 bar) phase? The temperature in my experiments is usually between 0 and 5°C. The stirring speed is around 500 rpm. Is the solubility given apart from...
  6. L

    What is the mass of potassium nitrate which crystallizes?

    Homework Statement 20g of saturated solution of potassium nitrate is cooled from 68 to 36 degree Celsius What is the mass of potassium nitrate which crystallizes? Potassium nitrate solubility per 100g of water 68 degree Celsius = 120g 38 degree Celsius = 60g Homework Equations I tried without...
  7. C

    Solubility of Calcium Oxalate in an Alcohol Solution?

    In searching through the literature for the solubility of calcium oxalate, I came across this post I am not sure where the people answering this question have gotten the information that calcium...
  8. B

    Help please with this precipitation exercise

    Knowing Ks=6⋅10−38 for Fe(OH)3 in neutral solutions, calculate the minimum pH of an acidic solution in order to completely dissolve 10 mg of Fe(OH)3. Data: Volume = 0.1 L. I set out the equation for the equilibrium constant. having first calculated the concentration or iron ions (9.35899*10-4...
  9. P

    Solubility-Pressure graph of Ammonia!

    I have searched to find out how the solubility of Ammonia changes with pressure, but haven't been able to find out. Though data about solubility change with temperature is available. One have told me that solubility of Ammonia varies little with pressure. But, I want to be assured about that...
  10. Z

    Calculating the Ksp of Calcium hydroxide at room temp

    Homework Statement I conducted a titration experiment in which 0.1g of KHP was dissolved in 50mL of distilled water and placed in an Erlenmeyer flask. I filtered a Ca(OH)2 solution (that was left out open on the lab benches for us to use) and put that into the burette and titrated. Ultimately...
  11. R

    Solubility of tartaric acid/sodium tartrate in high vs low pH

    Homework Statement So we did a lab in organic chemistry where we did a resolution experiment for enantiomers and in the separatory funnel we had sodium tartrate/tartaric acid left in the aqueous phase of the funnel. It asks why this compound is more soluble in high ph solutions as compared to...
  12. RoboNerd

    Dissociation vs solubility

    Homework Statement Hello all! Say I have an ion XY. I dissolve it in a solution. What is the difference between its dissociation or solubility, or are they the same? Seems my ap chem review book is using these two terms interchangeably and I am just plain confused. Thanks Homework Equations...
  13. Serena

    Good solubility database?

    HI, Do you have any suggestion for a good solubility database? I tried IUPAC-NIST but I can't find the data I need there (water-toluene, water-hexane, water-MEK mixtures at 40°C). I am also looking for the densities of the pure solvents at 40°C. Thank you
  14. vetgirl1990

    Why is methyl red soluble in water AND ether?

    I just had an extraction lab, and am confused how methyl red is soluble in both water and ether. My prediction was that methyl red would be only soluble in ether, but it actually dissolved into both layers. Looking at it's structure, it has a carboxylic group on one end, attached to a chain...
  15. A

    Dilution of titanium dioxide

    Hello fellow scientists.I am currently doing a project that requires me to make a stock solution of titanium dioxide which i will use to make different concentrations and measure absorbance and then plot a calibration curve which will be used to determine the concentration of Ti02 in an unknown...
  16. N

    Ka and water solubility

    why is Ka of benzoic acid greater than acetic acid in aqueous medium yet water solubility of benzoic acid is less than acetic acid . (water solubility of acetic acid is infinite) ?
  17. Dong Aleta

    A question about the special case of calcium hydroxide

    Hi! I am having trouble understanding how a substance only slightly soluble in water is considered as a strong base. Isn't the definition of a base a substance that will increase the amount of OH- in a solution? In that case, shouldn't calcium hydroxide be considered a weak base because of its...
  18. R

    Solubility of fluorides

    Homework Statement The fluoride which is most soluble in water is: a)CaF2 b)BaF2 c)SrF2 d)BeF2 Homework Equations none The Attempt at a Solution the answer given is D. but BeF2 is covalent in nature and is soluble in organic solvents. Due to more electropositivity of Ba, BaF2 will have more...
  19. Merlin3189

    Chloride Sulphate in "L S, B C L, S P A" ? Mnemonic?

    I came across this in a thread on Na & K carbonates "Basically, just remember, L S, B C L, S P A All potassium,nitrate salts are soluble.. however, chlorides,carbonates and sulphates are an exception.For chlorides, all chlorides are soluble except lead chloride and silver chloride..all...
  20. V

    Selective precipitation, purity and yield of precipitate

    Homework Statement An aqueous effluent contains 12 M Cd2+ and 10 M Mg2+ as solution of nitrates. Current practice is use NaOH to selectively precipitate the metals. (a) Is it feasible to get 0 Cd impurities in Mg ppt by using NaF instead of NaOH (back up your answer with adequate calculations)...
  21. Teemo

    Solubility and Precipitation of Unknown Ion

    Homework Statement A colorless solution is known to contain one of these ions. Which ion is present if adding dilute HCl produces a white precipitate that dissolves when the solution is warmed? (A) Ag+ (B) Cu2+ (C) Hg22+ (D) Pb2+ Homework Equations N/A The Attempt at a Solution I know it...
  22. E

    Solubility of Ammonia gas in Dimethyl Sulfoxide

    Hi Everyone, I'm writing a research plan for a college lab and I need the solubility of Ammonium Gas in Dimethyl Sulfoxide at STP and RTP. I've been searching internet and I haven't found anything. Please let me know the solubility or where I can find this information. Any help is greatly...
  23. E

    If Ammonia and Carbon Dioxide Gas are present, will (NH4)HCO3 form in any Polar Solvent?

    I know aqueous Ammonium Bicarbonate forms when NH4+ and HCO3- ions are present in water after they've dissolved from their gaseous states of NH3(g) and CO2(g). This occurs in the reaction: NH3(g) + H2O(l) + CO2(g) => (NH4)HCO3(aq) If Ammonia gas and CO2 are present above a polar organic...
  24. D

    Simple concentration problem but something's wrong

    Ok so I think I have a suitable answer to my question but because of certain circumstances I have reason to believe my answer is wrong. The question is: calculate the amount of phosphoric acid in mgH3PO4/L in a solution of concentration 2.92X10^-5 mol/L. seems pretty straight forward but...
  25. E

    Solubility in Relation to Partial Pressure vs. System Pressure

    Hi Physics Forums, The solubility of a gas according to Henry's Law depends on partial pressure. Would an increase in pressure in a system increase the solubility of a specific gas, even if the partial pressure of that particular gas doesn't change? The system described above increases in...