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Separation of a Mixture class 9

In a Mixture, the individual components retain their original properties. This is exploited to separate the Mixture into individual componen...

In a Mixture, the individual components retain their original properties. This is exploited to separate the Mixture into individual components.

Separation of a Mixture

What is the principle used in the separation of mixtures Class 8

The different in one more of the following physical properties of the constituents is utilized to separate the components of a Mixture.

  1. Physical state 
  2. Density 
  3. Melting and boiling point
  4. Solubility 
  5. Magnetic properties 
  6. Diffusion 
  7. Ability to sublime 
  8. Volatility 

Separation of a solid-solid Mixture 


Technique 

Solvent extraction


Principle Involved 

One component of the Mixture is soluble and the other is insoluble in a give solvent.


Examples 

  1. Mixture of sulphur (soluble) and sand (insoluble). Solvent: carbon disulphide (cs2).
  2. Mixture of Nh4Cl (soluble) and (insoluble) I2 solvent:water.

Technique
 
Magnetic Separation 


Principle Involved 

One component of the Mixture is a magnetic substance.


Examples

  1. Mixture of iron ore (magnetic) and sand.
  2. Mixture of cobalt (magnetic) and lead.


Separation of a solid-liquid Mixture 


Technique
 
Sedimentation and devastation

Principle 

The solid component is insoluble and heavier than the liquid component.

Example
  1. Mixture of sand and water.


Technique 

Distillation 

Principle 

Separation of Mixture containing a soluble solid by evaporation followed by condensation. They solid should not sublime 

Example
  1. Mixture of Nacl and H2

*Distillation is carried out in a special type of apparatus 



Example:

Separation of KCl from a solution of KCl and water.


Procedure

The KCl solution is taken in a distillation flask (X). 
The flask is carefully heated; The solvent evaporates and the water vapor condenses in Liebig's condenser ((Y). KCl remains in the distillation flask and the water is collected in the receiver flask.
Separation of component of ink by paper chromatography


Separation a liquid-liquid Mixture 

(A)Separating funnel 


Principle: Separation of immiscible liquid components using a separating funnel where liquids separate out due to different densities. 

Example

Separation of petrol (lighter) from water (heavier).  

Procedure  
  1. The liquid - liquid mixture is poured into a separating funnel clamped vertically and the mixture is allowed to stand. Clear layers of the liquids are formed as the liquid with higher density settles down at the bottom of the flask. 
  2. The nozzle tap is opened slowly and the heavier component is allowed to trickle down. The lighter component remains in the flask.
    Separation of immiscible liquids by Separating funnel


(B)Fractional distillation 

principal: Separation of two miscible liquid components using a distillation flask with a fractionating column using the difference in boiling points of the liquid components

Example

Laboratory separation of methanol from water. 

Procedure 
  1. The alcohol - water mixture is poured into a distillation flask and the flask is heated at a temperature which is equal to or more than the boiling point of alcohol but less than that of water.
  2. When the mixture in the flask is subjected to slow heating, alcohol being more volatile than water, gets vaporized first. As the vapours pass through the fractionating column. they get condensed and the liquid formed is collected in the receiver. Water remains in the distillation flask.
    Separation of immiscible liquids by fractional distillataion



Separation of a Gas - Gas Mixture


based on the physical properties of gases, different physical methods are adopted

(A) Diffusion 


Principle: Difference in densities of gaseous components.  

Examples: 

Co2 and H2

so2 and N2


(B) Dissolution in suitable solvents 


Principle: When a constituent is soluble in a liquid or reacts chemically with a liquid, it is dissolved in that solvent, from which it can be recovered by a chemical reaction.



(C) Preferential liquefaction  


Principle: Employed industrially for the separation of a homogeneous mixture of two gases, one of which liquefies under high pressure, when they are allowed to expand suddenly. 


(D) Fractional evaporation 


Principle: This process can be adopted when a mixture of two gases having different boiling points is liquefied by allowing it to expand suddenly under extremely high pressure, followed by evaporating the mixture at the respective boiling points of the constituent gases. 


Separation of a Liquid - Gas Mixture 

The solution of a gas in a liquid is called liquid - gas mixture

 

(A) Separation of a liquid - gas mixture by heating 

Principle: The solubility of a gas in a liquid decreases with the rise in temperature. 


Example

  1. The liquid - gas mixture (eg, water -Co2 ) is filled in a flask and heated gently so that the solution does not boil. 
  2. On heating, the solubility of the gas decreases and the dissolved gas is developed and collected. 


(B) Separation of a liquid - gas mixture by releasing pressure 


Principle: The solubility of a gas in a liquid can be increased by increasing external pressure and is decreased with the decrease in external pressure.  

Example


Cogas is dissolved in water by applying pressure in aerated drinks and this CO, gas comes out with a fizzing sound when the pressure is released.


Separation of a Mixture same important questions with answer

1. Distillation is the method used for separation of petrol from water.

Answer- false 

2.Glucose-water mixture can be separated by the method of  evaporation.

Answer- True


3. Drawing the Separation of acetone  from water why for fractional distillation, the following step are carried out. Arrange the following in the proper sequence.

(1) Water remains in the distillation flask. 

(2) The acetone - water mixture is taken in a distillation flask and the flask is heated at a temperature equal to or more than the boiling point of acetone but less than that of water.  

(3) As the vapors pass through the fractionating column, they get condensed and the liquid formed is collected in the receiver. 

(4) When the mixture in the flask is subjected to slow heating, acetone, being more volatile than water, gets vaporised first.


Answer-  2 4 3 1



4. Drawing the Separation of immiscible liquid-liquid mixture by a separating funnel, the following step are followed. arrange them in a proper sequence.

(1) The nozzle tap is opened slowly and the heavier component is allowed to trickle down.  

(2) The liquid - liquid mixture is poured into the separating funnel clamped vertically.  

(3) The lighter component remains in the flask.  

(4) The mixture is allowed to stand where clear layers of liquids are formed.  

(5) The liquid with higher density settles down at the bottom of the flask.


Answer- 2 4 5 1 3



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