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Explain Debey Huckel Onsager's law of the strong electrolyte.

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Last updated date: 20th Jul 2024
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Answer
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Hint: Before answering this question, we should what is Debey Huckel Onsager’s law. The relationship between molar conductivity ${{\lambda }_{m}}$at a particular concentration and molar conductivity $\lambda _{m}^{\circ }$at infinite concentration is Debey Huckel Onsager's law of the strong electrolytes. Debey huckel limiting law tells the behavior of strong electrolytes.

Complete answer:
In the year 1926, Debye and Huckel modified the theory and Onsager modified it further but all the postulates and original theory were retained. It was assumed that the electric field causes the distortion of the charge cloud from the spherical symmetry. After taking this into account, together with some specific requirements of moving ions like viscosity and electrophoretic effects. Onsager helped to derive a theoretical expression to give an empirical relation that is called kohlraush’s law for the molar conductivity ${{\lambda }_{m}}$.
${{\lambda }_{m}}=\lambda _{m}^{\circ }-K\sqrt{c}$
$\lambda _{m}^{\circ }$ is the limiting molar conductivity, K is an empirical constant and c is the electrolyte concentration. The limit of the infinite dilution means limiting. Onsager express it through-
${{\lambda }_{m}}=\lambda _{m}^{\circ }-(A+B\lambda _{m}^{\circ })\sqrt{c}$
Here, A and B are constants that are dependent only on known quantities like temperature, charges on the ions, and the dielectric constant and viscosity of the solvent. This is known as the Debye-Huckel-Onsager equation.

Note:
In Debey Huckel Onsager’s Law, To explain the non-ideal behavior of strong electrolytes, the mathematical way assumes that every ion is surrounded by an ionic cloud of oppositely charged ions, which retards the movement of ions in the medium. It is a method for the calculation of activity coefficients provided by this theory. This theory also helps with the other things to understand the diffusion in ionic media, change in the rate of ionic reactions when salts are added, and also biochemical reactions.