What Is a Solubility Curve Definition Graph Interpretation and Temperature Effect
Solubility curve is basically a data-based curve that is going to inform you about the amount of solute that will dissolve in a given amount of solvent at different temperatures. The most typical graphs or solubility curves are the ones that are based on the solid and gaseous solutes that are particularly dissolved in 100 grams of water.
What is Solubility?
Solubility is known as the maximum amount of solute which will dissolve in a given amount of solvent at a specific given temperature and pressure.
There are three different kinds of solutions which will result depending on how much of a particular solute is dissolved in the solvent.
As explained above, the solubility curve is the comparison of the amount of solute dissolved in a given amount of solvent at different temperatures. Here in this article,you will learn about the solubility curve in detail, which will provide you with all the basic information, including solubility rules chart, definition of solubility curve, graph of solubility, some problems of solubility curve and the main that is the importance if this solubility curve.
Solubility Curve Definition
The solubility curve definition chemistry is given as below:
The variation in the solubility of a given substance with the change of temperature is presented by the solubility curve. The solubility curve is the curved line that is drawn on the graph that shows the relationship between the temperature and the solubility of the substance at varying temperatures.
The graphical relationship between the solubility and the temperature is known as the solubility curve. The solubility curve determines the changes of the solubility of a solid at variable temperatures in a solvent. On the graph, the variations in temperature are to be plotted on the x-axis and the solubility is plotted on the y-axis. Temperature plays an important role in solubility since the solubility of a given substance is different at varying temperatures.
Solubility Graph
Let us now look at how the solubility graph looks. The solubility graph is shown as follows:
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How to read the Solubility Curve?
The solubility curve line shows you with a saturated solution. Saturated solution is basically the one with a full dissolved volume of solute in 100 grams of water. Any sim below this line is going to indicate the unsaturated solution. And all the solutions above this line shows you about the supersaturated solution.
Unsaturated Solution: An Unsaturated solution is the one that contains less amount of solute as compared to the maximum amount of solute that is capable of being dissolved for forming a solution. If more solute is added and it does not dissolve then the original solute is saturated and if more solution is added and it is dissolved then the original solution is considered to be an unsaturated one that is going to be shown below the line of solubility curve.
Supersaturated Solution: A chemical solution is considered as the supersaturated one only when the concentration of the solute in the solution exceeds the concentrations that is specified by the value equilibrium solubility. A supersaturated solution is basically in the metastable state. Any supersaturated solution can be brought back to its normal equilibrium state by forcing the excess solution to remove or separate from the solution.
Solubility Rules Chart
The general rules of solubility are given below. Let us look at each one of them and what they are.Most of the chloride salts are soluble. However, there are some exceptions like \[PbCl_{2}\], \[Hg_{2}Cl_{2}\] and \[AgCl\] .
The salts of \[Na^{+}, K^{+}\] and \[NH_{4}^{+}\] are all soluble.
All the sulfate salts are soluble. However, there are some exceptions which include \[BaSO_{4}, CaSO_{4}\] and \[PbSO_{4}\].
Almost all the nitrate (\[NO^{3-}\]) salts are soluble.
Almost all the hydroxide compounds are hardly soluble. The important exceptions in this category are NaOH and KOH. Barium hydroxide and calcium hydroxide, however, are moderately soluble.All the salts of sulfide, phosphate and carbonate are hardly soluble.
Importance of Solubility Curve
The solubility curve is used for determining the amount of substance that is deposited when the solution is cooled. Solubilities of different substances at a given temperature can be determined. The importance of solubility curves is discussed as follows.
Firstly, the solubility curve will help you to predict which substance crystallizes first from the solutions containing two or more solutes. Depending upon their solubility in the solution,
If you are given a substance whose solubility you need to find at a particular temperature then this solubility curve helps you.
There is a particular solubility process for every substance at different temperatures and this curve is going to help you to find the solubility process of a substance at a given temperature.
At a particular temperature if you are provided with a different number of substances then this solubility curve will help you to find the solubility at the same temperature.
This solution will not only provide you information about the saturation of a given substance but heside this it also provides with the information of supersaturated and unsaturated solution.
It gives you a clear idea of the fact that the solubility of a given substance changes with the temperature.
Solubility Curve Problems
Let us now look at some of the solubility curve problems in detail and how to solve them.
Example:
A solution with a precipitate of AgCl in equilibrium consists of \[1.0 \times 10^{-3}\] mol of \[Ag^{+}/L\] and \[1.3 \times 10^{-5}\] mol of \[Cl^{-}/ L\]. determine the solubility product of \[AgCl\].
Solution: The solubility product as per the definition is the product of the concentrations of the ions that are in equilibrium with the precipitate of a sparingly soluble substance.
For \[AgCl\],
\[K_{sp} = [Ag^{+}][Cl^{-}]= (1.0 \times 10^{-3}) ( 1.3 \times 10^{-5})= 1.3 \times 10^{-15}\]
Conclusion
Vedantu has covered all the aspects of solubility curve with examples. You can practice these examples to understand practically.
FAQs on Solubility Curve in Chemistry Explained with Graph and Concept
1. What is a solubility curve in chemistry?
A solubility curve is a graph that shows how the solubility of a substance changes with temperature. It typically plots temperature (°C) on the x-axis and solubility (grams of solute per 100 g of solvent, usually water) on the y-axis.
- It is commonly used for solid solutes in water.
- Each line on the graph represents a different substance.
- It helps determine whether a solution is unsaturated, saturated, or supersaturated at a given temperature.
2. What does a solubility curve tell you about a solution?
A solubility curve tells you the maximum amount of solute that can dissolve in a specific amount of solvent at a given temperature.
- Points on the curve represent a saturated solution.
- Points below the curve represent an unsaturated solution.
- Points above the curve represent a supersaturated solution.
3. How do you read a solubility curve graph?
To read a solubility curve, locate the temperature on the x-axis and move vertically until you reach the substance’s curve, then read the solubility value on the y-axis.
- Step 1: Identify the temperature (°C).
- Step 2: Move upward to intersect the correct substance curve.
- Step 3: Move horizontally to the y-axis to find solubility in g per 100 g water.
4. Why does solubility increase with temperature for most solids?
For most solid solutes, solubility increases with temperature because the dissolution process is usually endothermic.
- Heat provides energy to break intermolecular forces in the solid.
- More solute particles can interact with solvent molecules.
- According to Le Châtelier’s principle, adding heat favors the endothermic direction.
5. How does temperature affect the solubility of gases?
The solubility of gases in liquids generally decreases as temperature increases.
- Gas dissolution is usually exothermic.
- Increasing temperature adds kinetic energy, allowing gas molecules to escape.
- This is why warm soda loses CO2 faster than cold soda.
6. What is the difference between saturated, unsaturated, and supersaturated solutions?
A saturated solution contains the maximum amount of solute that can dissolve at a given temperature, while unsaturated and supersaturated solutions contain less or more than this amount.
- Unsaturated: Can dissolve more solute.
- Saturated: At equilibrium; no more solute dissolves.
- Supersaturated: Contains more dissolved solute than the equilibrium amount and is unstable.
7. How do you calculate the amount of excess solute using a solubility curve?
To calculate excess solute, subtract the solubility value from the actual amount of solute added at that temperature.
- Step 1: Find solubility from the curve (e.g., 40 g per 100 g water at 30°C).
- Step 2: Note the amount added (e.g., 55 g).
- Step 3: Excess = 55 g − 40 g = 15 g.
8. What factors affect solubility besides temperature?
Solubility is affected by temperature, pressure (for gases), and the nature of the solute and solvent.
- Pressure: Increasing pressure increases gas solubility (Henry’s law).
- Polarity: “Like dissolves like” — polar solutes dissolve in polar solvents.
- Intermolecular forces: Strong solute–solvent attractions increase solubility.
9. What is Henry’s law in relation to solubility curves?
Henry’s law states that the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the liquid. It is expressed as S = kP, where S is solubility, k is Henry’s constant, and P is pressure.
- Higher pressure increases gas solubility.
- Applies mainly to gases dissolved in liquids.
- Explains carbonation in soft drinks.
10. Can you give an example of using a solubility curve in real life?
A common real-life example of a solubility curve is the crystallization of sugar from a hot saturated solution as it cools.
- Hot water dissolves more sugar than cold water.
- As the solution cools, solubility decreases.
- Excess sugar forms crystals.
