

What Factors Affect Solubility?
Solubility is a crucial topic in chemistry, helping students understand why some substances dissolve in water while others do not. It appears in every chemistry syllabus and is linked with experiments, daily life, and exam questions.
What is Solubility in Chemistry?
A solubility refers to the maximum quantity of a solute (solid, liquid, or gas) that can dissolve in a specific amount of solvent at a certain temperature, forming a homogeneous solution.
This concept appears in chapters related to solutions, chemical equilibrium, and ionic equilibria, making it a foundational part of your chemistry syllabus.
Types of Solubility
Solubility can be classified into various types based on the state of solute and solvent:
- Solid in Liquid: Example – Sugar or salt dissolving in water.
- Gas in Liquid: Example – Carbon dioxide dissolving in soda water.
- Liquid in Liquid: Example – Alcohol mixing with water (miscible liquids).
- Sparingly Soluble and Insoluble: Some substances dissolve very little or not at all, such as oil in water.
Solubility Formula and Its Units
Solubility (S) is commonly measured by the amount of solute dissolved in a specific volume of solvent. The basic formula is:
S = (Mass of Solute Dissolved) / (Volume of Solvent)
Units: It is generally expressed in grams per 100 mL (g/100 mL) or moles per liter (mol/L).
For practice, if 10 g of salt dissolves in 100 mL of water, then solubility is 10 g/100 mL.
Solubility Curves and Charts
A solubility curve shows how the solubility of a substance changes with temperature. In general, solids become more soluble in water as temperature rises, but gases become less soluble. These curves help predict whether a solution is saturated or not at a given temperature.
Example: On a solubility chart, you will see a line for each substance showing how much dissolves at various temperatures. This visual is very useful during experiments and for exam questions.
Solubility Rules Table
Compound Type | Solubility in Water |
---|---|
Nitrates (NO₃⁻) | All soluble |
Chlorides (Cl⁻) | Soluble (except Ag⁺, Pb²⁺, Hg₂²⁺) |
Sulfates (SO₄²⁻) | Soluble (except Ba²⁺, Pb²⁺, Ca²⁺) |
Carbonates (CO₃²⁻) | Insoluble (except with Na⁺, K⁺, NH₄⁺) |
Hydroxides (OH⁻) | Insoluble (except with Na⁺, K⁺, Ca²⁺) |
Factors Affecting Solubility
- Temperature: For solids, higher temperature usually increases solubility; for gases, it decreases solubility.
- Pressure: Mainly affects gases—high pressure increases gas solubility in liquids (example: CO₂ in soda bottle).
- Nature of Solute and Solvent: Polar solutes dissolve best in polar solvents (like dissolves like).
- Common Ion Effect: The presence of a common ion decreases the solubility of salts.
- Intermolecular Forces: Stronger attractions increase solubility between similar molecules.
Applications and Real-Life Examples of Solubility
- Making tea, coffee, or cool drinks—all involve dissolving solids or gases in liquids.
- Pharmaceutical industry—tablets and syrups rely on dissolving drugs for absorption.
- Water purification through precipitation reactions.
- Effervescent drinks use dissolved CO₂ gas for bubbles.
Learning how solubility works helps in cooking, medicine, and understanding nature around us. Vedantu educators often use such examples during live classes.
Solubility Product (Ksp)
The solubility product (Ksp) is an equilibrium constant that applies to slightly soluble salts in water. It represents the maximum product of the ionic concentrations in a saturated solution. Unlike solubility (which is an actual amount dissolved), Ksp is a constant value used for calculations involving sparingly soluble compounds such as AgCl.
Frequent Related Errors
- Mixing up solubility (how much dissolves) and solubility product (the equilibrium constant).
- Assuming all solids become more soluble with heat (not true for all types).
- Confusing miscibility (liquid-liquid) with general solubility.
Uses of Solubility in Real Life
Solubility is important in everyday activities: dissolving vitamins in water, making solutions in labs, baking (sugar and salt behavior), and environmental science (desalination techniques). Understanding it also helps in chemical engineering and ecology.
Relation with Other Chemistry Concepts
Solubility is closely linked with saturation of solutions, solubility product (Ksp), and solution concentration. It also helps in understanding chemical equilibrium in reactions involving salts and ions.
Step-by-Step Reaction Example
Let’s see how sodium chloride (NaCl) dissolves in water:
1. Start with solid NaCl added to water2. NaCl dissociates into Na⁺ and Cl⁻ ions
3. Water molecules surround these ions and keep them separated
4. As more NaCl is added, a point comes when no more dissolves—this is saturation
5. Final Answer: Maximum amount of NaCl dissolved at that temperature shows solubility
Lab or Experimental Tips
Remember, “like dissolves like”—polar substances dissolve best in polar solvents. Stirring and gentle heating increase dissolution rate for solids. Vedantu educators recommend using solubility charts in lab for accurate measurements.
Try This Yourself
- Identify if NH₄Cl is soluble in water using the solubility rules table above.
- Check what happens when more sugar is added to saturated tea at room temperature.
- Draw a solubility curve for KNO₃ from textbook data and note its trend with temperature.
Final Wrap-Up
Today, we explored solubility—its definition, rules, applications, and related errors. Solubility is vital for understanding solutions, everyday mixtures, and advanced chemical equilibria. For deeper knowledge on solubility curves, saturation, and exam-oriented tips, visit the live classes and chemistry resources on Vedantu.
FAQs on Solubility – Meaning, Rules, and Examples in Chemistry
1. What is solubility in chemistry?
Solubility is the maximum amount of a solute that can dissolve in a solvent at a specific temperature, forming a homogeneous solution.
- Measured in grams per 100 mL or in moles per litre (mol/L)
- Depends on temperature, pressure, and nature of both solute and solvent
2. What factors affect solubility?
Several factors influence solubility, including:
- Temperature: Higher temperature usually increases solubility of solids but may decrease solubility of gases.
- Pressure: An increase in pressure generally increases the solubility of gases in liquids.
- Nature of solute and solvent: Polar solutes dissolve more in polar solvents, and non-polar in non-polar solvents.
3. What is a solubility curve?
A solubility curve is a graph showing how the solubility of a substance changes with temperature.
- Y-axis: Solubility (amount dissolved)
- X-axis: Temperature (°C)
- Used to predict how much solute dissolves at different temperatures
4. What are solubility rules?
Solubility rules are guidelines that predict whether an ionic compound will dissolve in water. Examples include:
- All nitrates (NO3-) are soluble.
- All sodium, potassium, and ammonium salts are soluble.
- Most chlorides are soluble except silver chloride.
5. What is the solubility formula?
The solubility formula calculates how much solute can dissolve in a solvent.
S = (Mass of solute / Mass of solvent) × 100 (for % solubility)
Solubility can also be expressed in molarity (mol/L) or grams per 100 mL.
6. Give an example of solubility in daily life.
Sugar dissolving in tea or water is a common example of solubility. Other examples are:
- Salt dissolving in water
- Oxygen dissolving in water for aquatic life
- Carbon dioxide dissolving in cold drinks
7. What is the difference between solubility and solubility product (Ksp)?
Solubility is the maximum amount of solute that dissolves in a solvent; solubility product (Ksp) is an equilibrium constant that indicates the degree to which a salt will dissolve.
- Solubility: an actual quantity (e.g., grams/100 mL)
- Ksp: a constant value for a specific salt at a given temperature
8. Why does the solubility of solids usually increase with temperature?
The solubility of most solid solutes increases with temperature because the dissolution process absorbs heat (endothermic), allowing more solute to dissolve at higher temperatures.
9. What is a saturated solution?
A saturated solution contains the maximum amount of solute that can dissolve at a given temperature.
- No more solute can dissolve unless temperature increases
- Extra solute remains undissolved as a residue
10. Can all substances dissolve in water?
No, only some substances dissolve in water. Water is a polar solvent and will mostly dissolve polar or ionic solutes. Non-polar substances like oil do not dissolve in water due to differing molecular properties.
11. How does pressure affect the solubility of gases in liquids?
Increasing pressure increases the solubility of gases in liquids. Higher pressure forces more gas molecules into the solution, as described by Henry’s Law.
12. What is a supersaturated solution?
A supersaturated solution contains more dissolved solute than is normally possible at that temperature, making it unstable.
- Excess solute may rapidly crystallize out if disturbed

















