Nemst distribution Law

Discuss the Nemst Distribution Law or Partition Law with reference to the theoretical aspects of liquid-liquid extraction support your answer with suitable examples. 

Nemst distribution law for regular mixtures and solvents ) it The non-electrolyte solute A in water A... 

The condition under which Nemst distribution law will not hold true is ... 

For a successful separation, all that is required is basically an immiscible solvent pair in which the components of the mixture have different partition coefficients according to the Nemst distribution law. Details about the instrumentation as well as numerous applications, including the separation of aroma precursors, can be found in the literature cited (23-28). 

The Nemst distribution law is applicable only to the species which have the same form in both the solvents. Now let the equilibrium in solvent II be... 

Chemical interactions in the organic phase, such as self-association or mixed-ligand-complex formation. Such chemical interactions do not invalidate the Nemst distribution law (Eqn. 20.3), but the extraction cannot be quantitatively described by that simple equation. It becomes necessary to know how each of the contributing reactions affects the extent of extraction. 

At sufficient dilution, yg —> 1 and Equation (2.3.4-2) simplifies to the Nemst distribution law (Equation 2.3.4-3), which has the same significance for extraction as Raoult s law for rectification ... 

Here, we will develop relationships describing the empirical measure of extraction, the distribution ratio, D, in terms of all of the relevant equilibrium relationships, for several typical extraction systems. We will see that such relationships can be quite complex. This is not a failure of the Nemst Distribution Law, however. It demonstrates that not only Kp, but all the relevant K values and accompanying concentration variables, are important. 

From these examples, as well as all the others, we can conclude that, while the expressions for D become complex in the presence of chemical processes other than simple phase distribution, this is not due to a failure in the Nemst Distribution Law, but a natural consequence of accounting for all the participating equilibria. 

Nemst distribution law is stated as - when a solute distributes itself between two nonmiscible solvents in contact with each other, there exists for similar, molecular species, at a constant temperature, a constant ratio of distribution between the two solvents irrespective of the amounts of the solute and the liquids. 

Explain Nemst distribution law. Work out formulae which you would apply in the case of (i) association and (ii) dissociation of the solute in one of the phases. Mention the applications of the distribution law in organic chemistry. 

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