SOLUTIONSSOLUTIONSTypes of SolutionsTypes of SolutionsSolubility and Solution ProcessSolubility and Solution ProcessEffect of Temperature and Pressure on Effect of Temperature and Pressure on SolubilitySolubility

Types of SolutionsTypes of Solutions

Gaseous SolutionsGaseous Solutions

Liquid SolutionsLiquid Solutions

Solid SolutionsSolid Solutions

In general, nonreactive gases or In general, nonreactive gases or vapors can mix in all proportions to vapors can mix in all proportions to give a gaseous mixture. give a gaseous mixture. Fluids that Fluids that mix with or dissolve in each other in all mix with or dissolve in each other in all proportions proportions are said to be are said to be miscible miscible fluidsfluids. Gases are thus miscible. (If two . Gases are thus miscible. (If two fluids do not mix but form two layers, fluids do not mix but form two layers, they are said to be they are said to be immiscible.immiscible.) Air, ) Air, which is a mixture of oxygen, nitrogen, which is a mixture of oxygen, nitrogen, and smaller amounts of other gases, is and smaller amounts of other gases, is an examle of a gaseous solutionan examle of a gaseous solution

Most liquid solutions are obtained by dissolving a gas, liquid, or solid in some liquid. Soda water, for example, consists of a solution of carbon dioxide gas in water. Ethanol, C2H5OH, in water is an example of liquid – liquid solution. Brine is water with sodium chloride (a solid) dissolved in it.

Types of SolutionsTypes of Solutions Liquid SolutionsLiquid Solutions

Gold- silver alloy is a solid solution. Dental filling alloy is a solution of mercury (a liquid) in silver (a solid), with small amount of other metals.

Types of SolutionsTypes of Solutions

Solid SolutionsSolid Solutions

Classification of Classification of SolutionsSolutions

ConcentratedConcentrated: A solution with a : A solution with a large amount of solute and small large amount of solute and small amount of solvent.amount of solvent.

DilutedDiluted: A solution with a small : A solution with a small amount of amount of solutesolute and large and large amount of amount of solvent.solvent.

Classification of Classification of SolutionsSolutions

Saturated solutionSaturated solution can not dissolve can not dissolve more solute at a given more solute at a given temperature.temperature.

If a solution is capable of dissolving If a solution is capable of dissolving more solute, it is called more solute, it is called unsaturated solutionunsaturated solution..

SolubilitySolubility

The solubilities of substances in The solubilities of substances in one another vary widely. You one another vary widely. You might find a substance miscible in might find a substance miscible in one solvent but nearly insoluble one solvent but nearly insoluble in another. As a general rule, “like in another. As a general rule, “like dissolves like”. That is, similar dissolves like”. That is, similar substances disolve one another.substances disolve one another.

SolubilitySolubility

For example oil is miscible in For example oil is miscible in gasoline. Both are mixture of gasoline. Both are mixture of hydrocarbon substances hydrocarbon substances (compounds of carbon and (compounds of carbon and hydrogen only). On the other hydrogen only). On the other hand, oil does not mix with water. hand, oil does not mix with water. Water is polar substance, Water is polar substance, whereas hydrocarbons are not.whereas hydrocarbons are not.

Definition of SolubilityDefinition of Solubility

SolubilitySolubility is the concentration of is the concentration of solute in saturated solution.solute in saturated solution.

For example, the maximum amount For example, the maximum amount of table salt which can dissolve in of table salt which can dissolve in 100 g of water is 36 g at 20 100 g of water is 36 g at 20 ooC.C.

It means that solubility of table salt It means that solubility of table salt at 20 at 20 ooC is 36g/100g water.C is 36g/100g water.

Effect of Temperature Effect of Temperature and Pressure on and Pressure on

SolubilitySolubilityIn general, the solubility of a In general, the solubility of a

substance depends on substance depends on temperature. For example, the temperature. For example, the solubility of ammonium nitrate in solubility of ammonium nitrate in 100 mL of water is 118 g at 0 100 mL of water is 118 g at 0 ooC C and 811 g at 100 and 811 g at 100 ooC. Pressure C. Pressure may also an effect on solubility.may also an effect on solubility.

Temperature EffectTemperature Effect

Most gases become less soluble in Most gases become less soluble in water at higher temperatures.water at higher temperatures.

Increased temperature causes an increase in kinetic energy. The higher kinetic energy causes more motion in molecules and escape from solution.

Temperature EffectTemperature Effect

solubility of gases usually decreases with increasing temperature

Temperature EffectTemperature Effect

Most ionic solids become more Most ionic solids become more soluble in water with rising soluble in water with rising temperature.temperature.The higher the kinetic energy of

water molecules, the better the chance they have of dislodging solid molecules and thereby getting them into solution. This is so because the water molecules collide with the solid and higher collision energies lead to more effective dislodgment and thus solubility.

Temperature EffectTemperature Effect

solubility increases with increasing

temperature

solubility decreases with increasing temperature

Solubility of solids

Pressure EffectPressure EffectEffect of pressure on solubility of solids and Effect of pressure on solubility of solids and

liquids is ignorable.However, solubility of liquids is ignorable.However, solubility of gases increases with increase in gases increases with increase in pressure.pressure.

When the pressure increased from P1to P2, concentration of gas molecules in solvent and therefore solubility of gas increases.

Examples:Examples:

500 g of water and 185 g of sodium 500 g of water and 185 g of sodium chloride are mixed to make a chloride are mixed to make a saturated solution at 25saturated solution at 25ooC. What C. What is the solubility of NaCl at 25is the solubility of NaCl at 25ooC?C?

Answer:Answer:

Solubility is defined as mass of solute Solubility is defined as mass of solute in 100g of solvent.in 100g of solvent.

500 g of water can dissolve 185 g of 500 g of water can dissolve 185 g of NaClNaCl

100 g of water will dissolve ? g of 100 g of water will dissolve ? g of NaClNaCl

?=?= = 37 g of NaCl = 37 g of NaCl

Examples:Examples:

Solubility of a solid at a certain Solubility of a solid at a certain temperature is 80 g/100 g water. temperature is 80 g/100 g water. How many grams of water and How many grams of water and solid are there in 90 g of solid are there in 90 g of saturated solution of this solid?saturated solution of this solid?

Answer:Answer:

100 g of water can dissolve max. 80 g 100 g of water can dissolve max. 80 g solid and forms 180 g of saturated solid and forms 180 g of saturated solution. So,solution. So,

180 g of solution contains 80 g of solid180 g of solution contains 80 g of solid90 g of solution will contain ? g of solid90 g of solution will contain ? g of solid

?= = 40 g of solid?= = 40 g of solid

90 – 40 = 50 g of water90 – 40 = 50 g of water

Examples:Examples:

Temperature (oC)

Solubility (g/100 g water)

40 60

20

50

The solubility curve of the solid X as function of temperature is give aside. According to graph,•How many grams of X can be dissolved in 200 g of water at 40oC ?•How much more X can be dissolved in the solution prepared by adding 40 g of X and 200 g of water at 60oC ?•At 60oC, saturated solution of X is prepared by 75 g of X. If the solution is cooled to 40oC, how many grams of X will precipitate?

Answer:Answer:How many grams of X can

be dissolved in 200 g of water at 40oC ?

According to graphat 40oC 100 g water dissolves 20 g

X200 g water ? g

X

?= = 40 g of X

Temperature (oC)

Solubility (g/100 g water)

40 60

20

50

Answer:Answer:

Temperature (oC)

Solubility (g/100 g water)

40 60

20

50

How much more X can be dissolved in the solution prepared by adding 40 g of X and 200 g of water at 60oC?

According to graphat 60oC 100 g water dissolves 50 g

X200 g water ? g

X

?= = 100 g of X

Since 40 g of X is dissolved before;

100 – 40 = 60 g of X can be dissolved in the solution at 60oC.

Answer:Answer:

Temperature (oC)

Solubility (g/100 g water)

40 60

20

50

At 60oC, saturated solution of X is prepared by 75 g of X. If the solution is cooled to 40oC, how many grams of X will precipitate?

According to graphat 60oC 100 g water dissolves 50 g

X ? g water 75 g X

?= = 150 g water

at 40oC 100 g water dissolves 20 g

X150 g water ? g

X

?= = 30 g of X

At 40oC 150 g of water can dissolve maximum 30 g of X. Therefore 75 – 30 = 45 g of X will precipitate

in this presentation…in this presentation…

States of solutionStates of solutiongasgasliquidliquidsolidsolid

Classification of solutionClassification of solutiondiluteddilutedconcentratedconcentratedsaturatedsaturatedunsaturatedunsaturated

Effect of temperature and pressure on Effect of temperature and pressure on solubilitysolubility