Ion mobility, Chemistry

Ion mobility:

Ion mobility is related to molar conductivity by the equations:

723_ion mobolity.png

which allows the mobilities, u+ and u- of the cation and anion to be determined from molar conductivity measurements at and away from infinite dilution. z+ and z- are the formal charges of the cation and anion respectively, so z+F and |z-F| are the magnitudes of the charges on a mole of cations and anions. The mobility is always positive (+) and is a measure of the terminal migration speed of an ion per unit applied electric field. This limiting speed is accelerating due to the field is exactly balanced by the viscous drag of the ions moving through the solution which for a spherical ions lead to the equations:

55_ion mobolity1.png

where e is the charge on the electron (-), so ze is the charge on the ions, η is the viscosity, a constant for any solvents which determines how easy it is for the ion to part the solvent molecule and move through solution and a is the hydrodynamic radius of the solvated ion.


H+/OH- mobility:

Hydroxide and Protons ions have anomalously high ionic molar conductivities and mobilities in comparison to all ions, and in particular for their size. That is as a result of the mechanism by which they move through solution, called the Grotthus mechanism (Fig. 1).


2320_ion mobolity2.png

Fig. 1. The Grotthus mechanism for (a) H+; (b) OH- ion motion in water. The arrows indicate the concerted proton movement when the field is applied.

Posted Date: 7/21/2012 2:21:27 AM | Location : United States

Related Discussions:- Ion mobility, Assignment Help, Ask Question on Ion mobility, Get Answer, Expert's Help, Ion mobility Discussions

Write discussion on Ion mobility
Your posts are moderated
Related Questions
conclusion for Werner''s coordination theory assignment

chemical reacation of sucrose

what is a crystal and why do crystals have regular faces?

Q. Show the Relationship between matter and energy? Ans. Albert Einstein described an intricate relationship between matter and energy. It is summarized in the famous for

GFAAS is often necessary to add modifiers in order to increase the sensitivity of the techniques.Giving example explain the principles used in the selection of such modifiers,be ca

Illustrate the salient aspects of ionic and metallic bonded crystals. Properties Ionic Metallic Bonding Force The

Classification based upon molecular forces: Depending on the intermolecular forces, the polymers have been categorized into four types. (a) Elastomers             (b) Fi

Structure of Aldehydes and Ketones Carbonyl carbon atom is connected to three atoms by sigma bonds. As these bonds use Sp 2 -orbitals, they found in the same plane and are 120°