Q1: What is the Theory of the experiment?
Answer:
The purification of lyophilic and lyophobic sols is performed using a dialysis method, in which colloidal particles are unable to pass through a parchment or cellophane membrane but electrolyte ions can.
Q2: What are Lyophilic Sols?
Answer:
The term lyophilic refers to a person who is fond of liquids. Lyophilic sols are those in which the dispersed phase and dispersion medium (water) has a high affinity. A colloidal solution made by dissolving starch in water, for example. The dispersion medium in this colloidal solution is water, and the dispersed phase is starch.
Q3: What is meant by the term Dialysis?
Answer:
Dialysis is the process of separating electrolytes from a colloid by allowing the latter to diffuse through an animal or vegetable membrane.
Q4: Why do we use parchment paper in the experiment?
Answer:
In this experiment, we use parchment paper because colloidal particles cannot pass through it while ions can, causing them to be separated.
Q5: What is the size of the cellophane sheet/parchment paper used in the experiment?
Answer:
A square sheet of size 30 cm × 30 cm.
Q6: What is the role of silver nitrate solution?
Answer:
It helps detect Cl– ions in the channel water.
Q7: How do you determine the presence of Na+ ions?
Answer:
When a solution of uranyl zinc acetate is introduced to the channel water, a yellow precipitate develops.
Q8: How do you determine the presence of Cl– ions?
Answer:
When a solution of uranyl zinc acetate is introduced to the channel water, a white precipitate appears.
Q9: Give examples of lyophilic and lyophobic sols.
Answer:
Lyophilic sols – Gum sol, starch sol, rubber, gelatin, egg albumin sol etc.
Lyophobic sols – Ferric hydroxide sol, aluminium hydroxide sol, arsenious sulfide sol etc.
Q10: How can we make dialysis fast?
Answer:
By circulating hot water rather than cold water, in the container or by applying an electric field across the dialyser.
Q11: Give the dispersed phase and dispersion medium of paints.
Answer:
Solid is the dispersed phase and liquid is the dispersion medium.
Q12: Write the dispersed phase and dispersion medium of butter.
Answer:
In solidified butter, the liquid is dispersed in solid. As a result, liquid serves as a dispersion medium, while solid serves as the dispersed phase.
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