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Solubility

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Last updated date: 22nd Mar 2024
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What is Solubility ?

The maximum amount of Solute that can dissolve in a known quantity of solvent at a certain temperature is its Solubility


A Solution is a Homogeneous mixture of one or more Solutes in a Solvent. Sugar cubes added to a cup of tea or coffee is a common example of a Solution. The property which helps sugar molecules to dissolve is known as Solubility. Hence, the term Solubility can be defined as a property of a substance (Solute) to dissolve in a given solvent. A Solute is any constituent which can be either solid or Liquid or gas liquified in a solvent.

 

Solubility Product

The term solubility product is generally applicable for frugally Soluble salts. It is the maximum product of the molar concentration of the ions (raised to their appropriate powers) which are produced due to dissociation of the compound.

 

At a given temperature the solubility product is constant. Lesser the value of solubility product indicates lower solubility and higher value of solubility product indicates greater solubility.

 

Solubility Definition

Solubility is a property referring to the ability for a given substance, the solute, to dissolve in a solvent.It is restrained in terms of the maximum amount of solute dissolved in a solvent at balance. The resulting solution is called a saturated solution. Certain substances are Soluble in all proportions with a given solvent, such as ethanol in water. This property is known as miscibility.Under numerous conditions, the balance solubility can be surpassed to give a so-called supersaturated solution, which is metastable.The solvent is frequently a solid, which can be a clean substance or a mixture.

 

  • Solubility of Gases In Liquids

Gas solubility in liquids involves the concept of gas dissolving in a solvent. Let us first define solubility. For any substance, solubility is the maximum amount of solute that can be dissolved in a given solvent at a particular temperature. Now our concern is gas solubility in liquids. The gas solubility in liquids is significantly affected by temperature and pressure and also by the nature of the solute and the solvent.

 

There are many gases that readily dissolve in water, while there are gases that do not dissolve in water under normal conditions. Oxygen is just sparingly Soluble in water whereas HCl or ammonia readily dissolves in water.

 

Other Types of Solubility

  • Solubility of Liquids In Liquids

Water is known as a universal solvent as it dissolves almost every solute except for a few. A few factors can influence the solubility of a substance.

 

Solubility is the new bond formation amongst the solute molecules and solvent molecules. In terms of quantity, solubility is the maximum concentration of solute that dissolves in a known concentration of solvent at a given temperature. Based on the concentration of solute dissolves in a solvent, solutes are categorized into highly Soluble, sparingly Soluble or inSoluble. If a concentration of 0.1 g or more of a solute can be dissolved in a 100ml solvent, it is said to be Soluble. While a concentration below 0.1 g is dissolved in the solvent is known to be sparingly Soluble. Thus, it is known that solubility is a quantitative expression and articulated by the unit gram/litre (g/L).

 

Based on solubility, different types of solution can be obtained. A saturated solution is a solution where a given amount of solute is completely Soluble in a solvent at a given temperature. On the other hand, a supersaturated solution is those where solute starts salting out or precipitates after a particular concentration is dissolved at the same temperature.

 

Factors Affecting Solubility:

The solubility of a substance hinges on the physical and chemical properties of that element. In addition to this, there are a few conditions which can manipulate it. Temperature, pressure and the kind of bond and forces in between the particles are a few among them.

  • Effect of Temperature on Solubility: 

By changing the temperature we can increase the Soluble property of a solute. Generally, water dissolves solutes at 20° C or 100° C. Sparingly Soluble solid or liquid substances can be liquified completely by raising the temperature. But in the case of gaseous substances, temperature inversely influences solubility i.e. as the temperature increases gases expand and escape from their solvent.

  • Forces and Bonds:

Like dissolves in like. The type of intermolecular forces and bonds vary among each molecule. The chances of solubility between two dissimilar elements are more challenging than the like substances. For example, water is a polar solvent where a polar solute like ethanol is easily Soluble.

  • Pressure:

Gaseous substances are much more influenced than solids and liquids by pressure. When the partial pressure of gas rises, the chance of its solubility is also hiked. A soda bottle is an example of where CO2 is bottled under high pressure.

  • Solubility of Solids In Liquids

It has been observed that solid solubility depends on the nature of the solute as well as the solvent. We frequently see that substances like sugar, common salt (NaCl), etc quickly dissolve in water while substances like naphthalene do not dissolve in water.

FAQs on Solubility

1. How is Solubility Related to Concentration Why is it Important to Know the Solubility of a Substance?

Solubility is the amount of solute that can dissolve in a given amount of solvent at a given temperature. The concentration of a solution is the amount of solute in a given amount of solution. A dilute solution has a low concentration of solute. The measure of solubility determines how substances dissolve into one another. The substance dissolving into the other is the solute and the substance being dissolved into is the solvent. These factors can accelerate the rate of solubility or they can prevent certain substances from being Soluble.

2. What is the KSP Formula and What are the Factors that Affect Solubility?

In general, MXb(s) ⇔ aM+b(aq) + bX-a(aq) is expressed as Ksp = [M+b]a[X−a]b. These expressions are called solubility product constant expressions because they involve the product of the equilibrium concentrations of the constituent ions, each raised to the power corresponding to the number of ions in the formula. Factors affecting solubility

  1. Temperature. Basically, solubility increases with temperature. 

  2. Polarity. In most cases solutes dissolve in solvents that have a similar polarity. 

  3. Pressure. Solid and liquid solutes. 

  4. Molecular size. 

  5. Stirring increases the speed of dissolving.

3. Do gases also dissolve in water and can we also call them Solute?

Water is an excellent solvent present on Earth. A wide number of substances are Soluble in it. Solid-state substances that can dissolve in water are very commonly known to everybody. Interestingly, there are also some substances that naturally occur in a gaseous state that also get dissolved in the water. Canon dioxide is a well-known gas to do so and is very popularly used in the production of soda water or soft drinks. Oxygen is also Soluble in water in sparing amounts but very essential in terms of the life system it supports in all water bodies. Ammonia is another known gas to dissolve in water.

4. Why are some substances that are Soluble in water not Soluble in other Liquids or vice versa?

Solving ability of any Liquid is determined by the polarity of the molecules of that Liquid. Water molecules are formed by the chemical combination of two hydrogen atoms with one oxygen atom. And because the hydrogen atoms are not in an exactly opposite position to each other so it exerts polar difference of charges on two sides. So any substance that also has some net charge value in its molecules will readily dissociate and get attracted to the oppositely charged side of the water molecule. But this phenomenon will not occur in Liquids consisting of molecules without any net charge.

5. What is a saturated Solution?

Water and any solvent that has the ability to dissolve a solvent can do so for a certain amount of Solute. This is essentially a function of the density of the solvent. As we mix a Solute in a solvent it the molecules of Solute get dissociated and get placed in the interspaces of solvent molecules. This in turn increases the density of the solvent. If we go on adding Solute then after a certain amount all the intermolecular spaces will get filled up and there will be no more spaces left for any extra space. At this limit when the solvent is not capable of dissolving any more Solute, it is called a saturated Solution.

6. What are the different factors that affect the Solubility of a Solute in a substance?

There are many that affect the Solubility of a substance in any solvent. By changing these factors we can successfully regulate the concentration of a Solute in the Solution. Temperature is the most common factor. As we studied earlier the Solubility of a substance depends on the density of the solvent so by increasing the temperature the density of solvent can be decreased and it can again dissolve more Solute. Likewise, pressure is another factor that influences the density of a Liquid.

7. Where can I find problem questions on Solubility and Solution?

The amount of Solute that is present in a Solution and the various factors that determine it are quantitative in nature. So these factors can be measured and are related to each other. This fact facilitates the formation of problem questions based on the known parameters of a Solution. Textbooks have a few questions based on this in the chapter exercises. Students can also get more questions to practice on the Vedantu website. These questions have been prepared by expert Chemistry teachers.