SOLUTION
It is a homogeneous mixture of two or more non-reacting substances having variable composition within certain limits.E.g. Sugar in water, salt in water etc.
COMPONENTS OF SOLUTION
-The substances used to make a solution are called its components. E.g. sugar in water. Here sugar and water are the components of sugar solution.
BINARY SOLUTION
If a solution consists of two components it is known as binary solution.
SOLUTE AND SOLVENT
The component taken in lesser amount is called solute whereas the component taken in excess amount is called solvent. E.g. sugar in water. Here water is solvent and sugar is solute.
SOLUTE-TYPES.
1.VOLATILE SOLUTES:- Those solutes which can be easily converted into vapors like alcohol, acetone etc.
NON-VOLATILE SOLUTES:-Which cannot be converted into vapors like sodium chloride etc.
SOLUBILITY
It is the maximum number of moles of solute per liter of the solution to form a saturated solution at a particular temperature. Its units are mole per liter.
MISCIBLE AND IMMISCIBLE
When a liquid can completely dissolve in another liquid the two liquids are miscible. Two liquids that can never mix to form a solution are called immiscible. e.g. water and alcohol are miscible whereas water and oil are immiscible.
CONCENTRATION OF SOLUTION
The amount of solute present in the solution is known as concentration. There are various methods to express the concentration of a solution. The most important method among them is molarity.
DILUTE SOLUTION
Dilute solution contains very small amount of solute like one table spoon of sugar in a jug of water.
CONCENTRATED SOL
Concentrated solution contains large amount of solute like five table spoons in a cup of water
METHODS:CONCENTRATION
(1)STRENGTH
(2)VOLUME PERCENTAGE
(3)MASS PERCENTAGE
(4)MASS VOLUME PERCENTAGE
(5)PARTS PER MILLION
(6)MOLARITY
(7)MOLALITY
(8)MOLE FRACTION
(9)NORMALITY
(10)FORMALITY
STRENGTH
It is the amount of solute present per litre of the solution. It is expressed as gL-1
MOLARITY
It is defined as the number of moles of solute dissolved per litre of solution. It is expressed by the symbol M.Its units are mol/L.
Here MB is molecular mass and WB is the given mass of solute.
VOLUME PERCENTAGE (v/v)
IIt is defined as volume of the solute in milliliters present per 100 ml
MOLALITY
It is defined as number of moles of solute present per kg of the solvent. It is denoted by symbol “m”.Its units are mol/kg.It does not change with temperature.
NORMALITY
Normality of a solution is defined as the number of gram equivalents of a solute dissolved per litre of the solution. It is expressed by the symbol N.Its units are gram eq /L.
Q:- Molality is preferred over molarity to express concentration of the solutions.why ?
OR
Q:- Molality is same at all temperatures, molarity is not. Give reason.
Ans:- Molality is expressed in terms of mass of the solvent which is independent of temperature. On the other hand molarity is expressed in terms of volume of the solution which increases or decreases with temperature.
Q:- What is the effect of temperature on molarity of solution?
Ans:- Molarity of the solution decreases because volume of the solution increases with the increase in temperature.
Q:- When Molality and molarity become equal?
Ans:- When density of the solution is equal to unity.
Q:- How can you calculate number of moles ?
Q:- How can you calculate number of gram equivalents ?
Q :-Differentiate between molarity and molality?
| MOLARITY | MOLALITY |
|---|---|
| Volume of the sol is considered. | Mass of the sol is considered. |
| It changes with temperature | It does not change with temperature |
MOLE FRACTION
It is the ratio of number of moles of one component to the total number of moles of all the components present in the solution. It is denoted by the symbol chi.If a solution contains two components A and B and suppose nA are the moles of A and nB are the moles of B then :
PARTS PER MILLION (ppm)
It is defined as the amount of the solute present in one million parts of the solution. It is used when solute is present in very small amount.
MASS PERCENTAGE
It is defined as amount of solute in grams present per hundred grams of the solution.
FORMALITY
It is defined as number of gram formula mass of solute dissolved per litre of the solution. It is denoted as F.It is used for ionic compounds in place of molarity.
PRESSURE
It is the force per unit area. P=F/A).The earth is surrounded by a thick layer of air called atmosphere, which exerts pressure on the surface of earth due to gravity. This pressure is known as atmospheric pressure. The SI unit of pressure is pascal.
BAROMETER
The instrument used to measure atmospheric pressure is known as barometer.
MANOMETER
The instrument used to measure of a gas is known as manometer.
VAPOR PRESSURE
The pressure exerted by the vapors above the surface of a liquid is known as vapor pressure.
TERMS FOR VAPOR PRESSURE
V. P of pure component A = PA ̊
V.P of pure component B = PB ̊
Partial V.P of component A = PA
Partial V.P of component B = PB
Total V.P of the solution = PS
Other Topics :Solution
Henry's Law Click Here for RAOULT'S LAW Relative Lowering in Vapor Pressure
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