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Lyophobic means a water-repelling molecule. At the same time, sols are the heterogeneous system of colloids which includes solid as the dispersed phase and a liquid as the dispersion medium. The lyophobic sols are a crucial part of surface chemistry. Along with lyophilic, lyophobic is one of two major categories of colloids. You will learn about lyophobic sols, their properties, their preparations, along with some other topics from the curated lyophobic sols study material.
What are lyophobic sols?
Colloid science has been classified into two classes: lyophobic and lyophilic. Sols are one specific form of collidal molecules. In simpler words, sol is a colloid of solid in a liquid. If the liquid is taken as the dispersed medium, they are termed hydrophobic sols. Lyophobic sols are highly water-repelling and unstable in their natural form. However, several processes and reactions are used, and electrolytes are added to neutralise their biological nature. These processes are irreversible in nature; hence lyophobic sols are also termed irreversible sols. Gold, silver iodide, and ferric hydroxide are common examples of Lyophobic sols.
Uses of lyophobic sols
As lyophobic sols are quite muddy liquids and water-repelling components, they’re used in lyophobic sols significantly. Sols of different lyophobic colloids are used for various purposes, including multiple inks, muddy water, blood, etc. are lyophobic sols.
Preparation of Lyophobic sols
Unlike lyophobic sols, they can’t be prepared by shaking or direct mixture. Some unique methods are implied to obtain sols. Lyophobic sols are received after the hydrolysis of elements with boiling distilled water. The reaction produces particles processed through agglomeration to produce larger colloidal-diameter particles. Absorption of positively charged ions occurs during the process to give positive charges to sols and attain stability. Hydrochloric acid is created during hydrolysis and should be eliminated from the sol since it destabilises the solution.
How is Ferric Hydroxide sol made?
To prepare: Lyophobic sol of Ferric Hydroxide.
Procedure: Firstly, boil 100 ml of plain water in a 250 ml beaker. After boiling, you can put two grams of ferric hydroxide powder and stir it well. You’ll get the solution of ferric hydroxide.
Further, take 100 ml of plain water in another beaker and boil it. Now, put the solution of the first beaker into this drop by drop. Stir constantly during combining. Lastly, continue to boil the water until a brown sol is produced. Lastly, dialysis will be processed to purify the sol and maintain its stability.
Characteristics of Lyophobic sols
As discussed, lyophobic sols possess several novel properties among other colloidal solutions. Lyophobic sols are water-repelling particles. These are easily flocculated and coagulated by adding small chunks of electrolytes in the medium. However, the general nature of the sol depends on the nature and valence electrolytes. The viscosity of lyophobic sols is mostly the same as the medium. Moreover, the surface tension is also the same.
Initially, when the lyophobic sol is coagulated the first time, the homogenous mixture becomes turbid and further turns to the distinct non-homogenous solution. Owing to the sensitivity of lyophobic sols towards electrolytes added in sol medium, these sols are called electrostatic colloids. Moreover, lyophobic sols can rapidly turn into lyophilic sols when a sole electrolyte of different properties is added to the complete solution.
Lyophobic sols Stability
Lyophobic sols possess stability based on forming a thick double layer around them that can withstand agglomeration. Generally, lyophobic sols acquire stability through a process called Peptization. However, the process depends on small amounts of specific ions in the system. The stability acquired can be destroyed if electrolytes other kinds of electrolytes are added to the medium.
Conclusion
We discussed lyophobic sols’ necessary aspects and learned about their preparation, properties, and other general concepts. Moreover, we learned that lyophobic sols are water-repelling colloids that are highly unstable naturally. Lyophobic sols must process several processes and reactions to attain stability or alter their properties. We also skimmed through the preparation, where we learned the preparation of lyophobic sols of ferric hydroxide. Lastly, the noble properties and stability of the lyophobic sols were also discussed in this curated lyophobic study material.
