Answer to Question #61128 in Physical Chemistry for Amit Sharma

Question

State distribution law. Give its applications.

Answer 1

Answer:
Distribution law or the Nernst’s distribution law gives a generalization which governs the distribution of a solute between two non miscible solvents. This law was first given by Nernst who studied the distribution of several solutes between different appropriate pairs of solvents. The statement of the law is:
"If a solute X distributes itself between two non miscible solvents A & B at constant temperature & X is in the same molecular condition in both the solvents, then: concentration of X in A / Concentration of X in B = Kd".
Where Kd is called the distribution coefficient or the partition coefficient. If C1 denotes the concentration of solute in solvent A & C2, the concentration of X in B; Nernst’s distribution law can be expressed as C1/C2 = Kd.
Applications of Nernst’s Distribution law:
1) solvent extraction;
2) partition chromatography;
3) release of drug from dosage forms;
4) passage of drug through membranes;
5) preservation of emulsions and creams;
6) formation of solubilized system.