Physical properties of colloidal solutions: Heterogeneous character: Colloidal particles being larger than molecules form heterogeneous mixture composed of particles of dispersed phase and dispersion medium. The phenomenon of Tyndall effect, electrophoresis and electro-osmosis confirm heterogeneity of colloidal systems. Stability: Colloidal sols are quite stable. Only a few colloidal particles ...

Peptization is a process of passing of a precipitate into colloidal particles on adding suitable electrolyte. The electrolyte added is known as peptizing agent. A few examples of sols obtained by peptization are given below: A reddish brown colored colloidal solution is obtained by adding small ...

When some solid is dispersed into a medium in which the solid substance is otherwise insoluble such that after dispersion, the size of the colloidal particles lies in the colloidal range, the system is called a colloidal dispersion. Examples of colloidal dispersion are gold sol, ...

Differences between lyophilic and lyophobic sols are as follows: PROPERTIES LYOPHILIC SOLS LYOPHOBIC SOLS Ease of preparation Prepared easily by directly mixing with the liquid dispersion medium. Cannot be prepared directly. Prepared by special methods only. Solubility They are quite stable and are not easily precipitated or ...

Adsorption finds extensive applications both in research laboratory and in industry. A few applications are discussed below: In preserving vacuum: In Dewar flasks activated charcoal is placed between the walls of the flask so that any gas which enters into the annular space either due to ...

Adsorption involves attracting molecules of adsorbate on surface of the adsorbent. Due to this, energy is released and thus heat of adsorption is negative i.e. adsorption is always exothermic. Further physical adsorption involves weak forces of attraction, heat evolved is less whereas chemical adsorption involves ...

Factors Affecting Adsorption of Gases by Solids: Almost all the solids adsorb gases to some extent. However, the exact amount of a gas adsorbed depends upon a number of factors, as briefly explained below: 1. Nature of surface area of the adsorbent: It is observed that the same gas ...

Positive adsorption: In case of adsorption by solids from the solutions, mostly the solute is adsorbed on the surface of the solid adsorbent so that the concentration of solute on the surface of the adsorbent is greater than in the bulk. This is known as positive ...