The main difference between True Solution and Colloidal Solution is that True Solution is homogeneous single phase system and Colloidal Solution is a heterogenous two-phase system.
True Solutions vs. Colloidal Solutions
A true solution is a homogeneous mixture while a colloidal solution is a heterogeneous mixture. The true solution is one phase system whereas Colloidal solution is a two-phase system. The true solution is one in which solute is dissolved into solvent whereas Colloidal solution is a two-phase system in which one phase is dispersed into another phase. The true solution consists of solute and solvent; on the other hand, Colloidal solution consists of the dispersed phase and the dispersion medium. The true solution is transparent in appearance while Colloidal solution is translucent in appearance. The true solution contains particles which are invisible to the naked eye whereas Colloidal solution contains particles which are visible to the electron microscope. True solution undergoes electrolysis while Colloidal solution undergoes cataphoresis. True solution color is the color of salt dissolved in the solvent while Colloidal solution color depends upon colloidal particles size.
What is True Solution?
The true solution is the homogeneous mixture. The true solution is prepared by a combination of two or more components. The true solution has solute and solvent. Among the two components of the true solution, the solute is present in smaller amount and solvent is present in large amounts but in some cases, an exception is there. Solute in True solution can be a solid, liquid or gas and the same is true for solvent. When the two components of True solution are combined then the environment of both components is changed for the dissolution. The solute molecules get separated from the similar molecules and after that solvent molecules surround them. The solvent molecules also get separated from other similar molecules sufficiently and in this way create a space to accommodate the molecules of solute. The solute is dissolved in solution only when the intermolecular forces in solute-solute and solvent-solvent are overcome by intermolecular forces in solvent-solute. If the solute is polar then the intermolecular forces are stronger and solute would dissolve in a solvent if the solvent-solute intermolecular forces are stronger than the intermolecular forces in polar molecules of solute. This means solvent should also be polar. True solutions are formed on the basis of the principle of solubility that is like dissolves like. The strength of True solution is expressed on the basis of the molarity , molality, normality or the on basis of mass or volume of solute dissolved in specific mass or volume of solvent. The strength of the True solution can be expressed on the basis of percentage.
What is Colloidal Solution?
A colloidal solution is a system in which one substance is dispersed throughout another as particles. The dispersed substances make dispersed phase and substance in which the dispersed substances are dispersed make dispersion medium. Colloidal solutions are classified on the basis of the physical state of the two substances i-e dispersed and dispersion substances. One substance is dispersed into another only when there is considerable contact between two substances. The colloidal solutions are of two types lyophobic and lyophilic Colloidal solutions but instead of these two general terms are used such as hydrophobic and hydrophilic. Hydrophilic colloidal solutions are those in which there is an affinity of the dispersed particles for the dispersion medium. Hydrophobic colloidal solutions are those in which there is a no or little affinity of the dispersed particles for the dispersion medium. Hydrophilic colloidal solutions are thermodynamically stable because of the affinity of the dispersed particles for the dispersion medium. So hydrophilic colloidal solutions are formed spontaneously as the dispersed particles are added to water. Hydrophilic colloidal solutions show spontaneous coalescence as the dispersed particles are added to water. The interaction in the particles of Colloidal solution is due to some forces such as van der walls forces, entropic forces, steric forces, excluded volume forces, and electrostatic interactions. The colloidal solution can be prepared in two ways. Colloidal dimensions are achieved through the spraying, milling, and application of shear like shaking or high shear mixing. Small dissolved molecules can be condensed into larger colloidal particles by a process such as redox reactions, precipitation, and condensation.
Starch dissolved in water
- True solution constitutes a single phase system while Colloidal solution constitutes a two-phase system.
- True solution characteristics are a homogenous mixture; on the other hand, Colloidal solution characteristics is a heterogeneous mixture.
- The true solution has solute and solvent whereas Colloidal solution has dispersed and the dispersion medium.
- The true solution has a solute particle size less than 1nm in diameter while Colloidal solution has dispersed phase particle size in the range of 1-1000nm.
- True solution appears transparent while Colloidal solution appears translucent.
- The true solution has the property of electrolysis while Colloidal solution does not possess such property.
- True solution particles are invisible to the naked eye while Colloidal solution particles are visible to the electron microscope.
The conclusion of the above discussion is that True solution and Colloidal solution are homogenous and heterogeneous mixtures respectively and find their use in chemistry and pharmaceutics.