Jnanendra Chandra Ghosh

Bio: Jnanendra Chandra Ghosh is an academic researcher. The author has contributed to research in topics: Conductivity & Aqueous solution. The author has an hindex of 3, co-authored 6 publications receiving 61 citations.

Free Volume and Entropy in Condensed Systems III. Entropy in Binary Liquid Mixtures; Partial Molal Entropy in Dilute Solutions; Structure and Thermodynamics in Aqueous Electrolytes

Abstract: The ideas of the first and second papers in this series, which make it possible to interpret entropy data in terms of a physical picture, are applied to binary solutions, and equations are derived relating energy and volume changes when a solution is formed to the entropy change for the process. These equations are tested against data obtained by various authors on mixtures of normal liquids, and on solutions of non‐polar gases in normal solvents. Good general agreement is found, and it is concluded that in such solutions the physical picture of molecules moving in a ``normal'' manner in each others' force fields is adequate. As would be expected, permanent gases, when dissolved in normal liquids, loosen the forces on neighboring solvent molecules producing a solvent reaction which increases the partial molal entropy of the solute.Entropies of vaporization from aqueous solutions diverge strikingly from the normal behavior established for non‐aqueous solutions. The nature of the deviations found for non‐polar solutes in water, together with the large effect of temperature upon them, leads to the idea that the water forms frozen patches or microscopic icebergs around such solute molecules, the extent of the iceberg increasing with the size of the solute molecule. Such icebergs are apparently formed also about the non‐polar parts of the molecules of polar substances such as alcohols and amines dissolved in water, in agreement with Butler's observation that the increasing insolubility of large non‐polar molecules is an entropy effect. The entropies of hydration of ions are discussed from the same point of view, and the conclusion is reached that ions, to an extent which depends on their sizes and charges, may cause a breaking down of water structure as well as a freezing or saturation of the water nearest them. Various phenomena recorded in the literature are interpreted in these terms. The influence of temperature on certain salting‐out coefficients is interpreted in terms of entropy changes. It appears that the salting‐out phenomenon is at least partly a structural effect. It is suggested that structural influences modify the distribution of ions in an electrolytesolution, and reasons are given for postulating the existence of a super‐lattice structure in solutions of LaCl3 and of EuCl3. An example is given of a possible additional influence of structural factors upon reacting tendencies in aqueous solutions.

The Yukawa potential

Abstract: The Yukawa potential, φ(r)=A(λr)-1eλr, has three important mathematical properties that are apparently unrelated but, in fact, closely linked These properties have led to the appearance of the potential in a great variety of different physical problems These ramifications are discussed in roughly chronological order The potential is generalized to spaces of dimensionality other than 3, and the properties of this generalized potential are explored

The Hofmeister series: Specific ion effects in aqueous polymer solutions

Abstract: Specific ion effects in aqueous polymer solutions have been under active investigation over the past few decades. The current state-of-the-art research is primarily focused on the understanding of the mechanisms through which ions interact with macromolecules and affect their solution stability. Hence, we herein first present the current opinion on the sources of ion-specific effects and review the relevant studies. This includes a summary of the molecular mechanisms through which ions can interact with polymers, quantification of the affinity of ions for the polymer surface, a thermodynamic description of the effects of salts on polymer stability, as well as a discussion on the different forces that contribute to ion-polymer interplay. Finally, we also highlight future research issues that call for further scrutiny. These include fundamental questions on the mechanisms of ion-specific effects and their correlation with polymer properties as well as a discussion on the specific ion effects in more complex systems such as mixed electrolyte solutions.