Kuppusami, J. (1985) Ultrasonic-studies on concentrated solutions up to saturation role pf internal pressure and free volume in solutions. PhD thesis, Madurai-Kamaraj University.

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At present, none of the theories on liquids and non-electrolytes is directly applicable to the behavior of electrolyte solutions. Even Debye-Huckel theory breaks down in moderately and highly concentrated solutions of electrolytes. It was felt that internal pressure, which is the resultant of attractive and repulsive forces, may throw more light in understanding the behavior of electrolyte solutions. For the first time, in this thesis, an attempt has been made to show the importance of internal pressure in understanding the fundamental physic-chemical properties of electrolyte solutions. Studies were carried out on nine electrolytes in a wide range of concentrations including saturation and for comparison, non electrolyte viz. glucose was chosen. Based on dimensional analyses of the situation when ultrasonic waves are propagated through a liquid medium, an expression for the free volume Vf has been obtained as Vf = (M u / Kη) (3/2) And an expression for the internal pressure, πi viz. πi = b R T (Kη/u)(1/2) P(2/3)/M(7/6) has been deduced. Both Vf and πi can be computed from easily measurable parameters like u, the ultrasonic velocity η, the viscosity and p, the density. In all the cases, a general Quadratic relation between internal pressure ( as also free volume ) with molal concentration was observed while the temperature dependence was found to be exponential. An interesting observation has been at any concentration, with variation in temperature, πi. Vf0.228 = constant (≈ 2240) This shows the complementary nature of πi and Vf. A quantitative relation between the electrolytic conductance and internal pressure was observed and the concentration as well as the temperature dependence of equivalent conductance was found to obey the generalized relations. Similarly, a quantitative relation between the activity coefficient and πi was obtained and this holds up to the highest concentration. From a study of saturated solutions, a simple relation was found between the solubility and πi at any temperature which will fix the state of saturation. From these studies, it was concluded that both πi and Vf are the two thermodynamic variables characterizing the behavior of electrolyte solutions

Item Type: Thesis (PhD)
Uncontrolled Keywords: Role of internal pressure and free volume
Subjects: Electrodics and Electrocatalysis
Electrochemical Materials Science
Depositing User: Dr. N Meyyappan
Date Deposited: 13 Jun 2012 05:00
Last Modified: 13 Jun 2012 05:00
URI: http://cecri.csircentral.net/id/eprint/2822

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