Solubility Test

Solubility

Dr. Vikas Saroch

Tuesday, April 11, 2023 SOLUBILITY 2

OBJECTIVES

• Try to understand the meaning • Different types • Procedure • Importance of solubility in Ayurveda


History

• IUPAC (Commission on Solubility Data) adopted,

at its formation in 1979

• Goal of preparing compilations of all experimental

determinations of solubility reported in the

world's chemical literature

• Evaluating data critically

• Made some standard


Description of the Instrument


SOLUBILITY• An ability of a substance to dissolve. • In the process of dissolving, the substance

which is being dissolved is called a solute. • Substance in which the solute is dissolved is

called a solvent. • A mixture of solute and solvent is called a

solution.• Degree to which a substance dissolves in a

solvent to make a solution (usually expressed as grams of solute per liter of solvent).


• When we insert sugar into water it will dissolve

Here :• Sugar is the solute• Water is the solvent


Solution

• A solution is a homogeneous mixture of two or

more substances.

Isotonic : Two solutions that have the same

concentration of a solute

Hypertonic : One of two solutions that has a higher

concentration of a solute

Hypotonic solutions : One of two solutions that has

a lower concentration of a solute


Solubility As Chemists Understand

• Understood as a maximum amount of solute

that dissolves in a solvent so

called equilibrium.

• In chemistry an equilibrium is a state where

reactants and products reach a balance - no

more solute can be dissolved in the solvent in

the set conditions (temperature, pressure).


• Take one liter of water and start dissolving salt in it

(chemical formula of salt is nacl)

• Temperature of water is 25oc

• Pressure is 1 ATM (atmosphere - standard pressure in the

open air on earth)

• Should be able to dissolve exactly 357.00 grams and not a

gram more.

• Rest of the salt will stay on the bottom as residue and will

not dissolve.

• Solubility of salt in water is therefore 357.00g/L.


• When this amount of salt is dissolved the

solution reaches its equilibrium.

• Every chemical substance which dissolves in

water has a fixed solubility.

• If it does not dissolve - its solubility is zero.

• Many of these solublities have been measured

and special charts are produced displaying

solubility of many substances at once.


Miscible And Immiscible Substances

• Some substances, like water and alcohol, can be

mixed together and create a homogenous phase in

any proportion.

• A solubility measure cannot be applied to such two

substances. Such substances are called miscible.

• On the other hand if two substances cannot be

mixed together (like water and oil), they are called

immiscible.


Why do things dissolve?

• Intermolecular forces

• Molecules of the solute are inserted into a solvent and

surrounded by its molecules.

• Molecular bonds between molecules of solute (ie. Sugar)

have to be broken and molecular bonds of the solvent also

have to be disrupted. Both of these require energy.

e.g.

• Sugar and water

• Salt and water


Solubility Rules

• To determine solubility of organic compounds usually the rule Like dissolves like is applied.

• Means that a solute will dissolve best in a solvent that has the same or similar polarity.


Factors Affecting SolubilityTemperature : Solubility increases with

temperaturePolarity : "Like Dissolves Like“• In most cases solutes dissolve in solvents that

have a similar polarity. • Non polar solutes do not dissolve in polar

solvents Pressure : Pressure does not affect solubility. Molecular size : Larger particles are generally

less soluble.


Stirring :• Stirring does not have an affect on solubility of

a substance• Stirring increases the speed of dissolving.


Applications

• Ore processing

• Pharma industry

• Separating mixtures (a mixture of salt sodium

chloride and silica)


Organic Qualitative AnalysisSolubility Tests

• Performed on every unknown

• Extremely useful in determining the nature of

the major functional groups present in the

unknown compound.

• Very simple

• A small amount of sample


Common Solvents

• Water• Ether • 5% NaOH • 5% NaHCO3

• 5% HCl• 96% H2SO4


Solubility of Bhasma

Dilute Acetic Acid

Dilute HCL

Sodium Hydroxide

Potassium Hydroxide

Ammonium Hydroxide

Carbonated Water


Procedure

• A pinch of bhasma was taken in a dry test

tube

• 1ml of solvent added

• Shaken for 1min

• Observed for solubility , non-solubility and

sparingly solubility


Rajata Bhasma

• Distilled water

• Methanol

• Petroleum Ether

• Acetone

• Benzene

• Toluene

• Chloroform*

• Normal Saline*

• Triphala Kwath*

• Ethyl Alcohol

• Xylene

• Carbon Tetra Chloride


Limitations , Precautionary Measures

• Selection of proper solvent and solute

• Proper media

• Cant be applied specially in bhasma

• More suitable for plant extractive


Conclusion • Solubility an important analytical procedure.

• Gauge absorption of substances in body.

• Selection of ideal solvent.

• Can be taken as a measure for standardization

of raw herbal drugs.


Thank u………

Solubility Test

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