--%>
Assignment Help - homework help

How to calculate solutions ionic mobilities?

Transference numbers and molar conductors can be used to calculate ionic mobilities.

This tables under is giving the transference numbers for positive ions at 25 degree C and the values obtained by extrapolation to infinite dilution:

948_Solution ionic mobilities.png 

Molar ionic conductances and ionic mobilities at infinite dilution and 25 degree C.

1491_Solution ionic mobilities1.png 

Values can now be obtained for the contributions the individual ions of an electrolyte make to the molar conductance. The empirical law of Kohlrausch implies that a infinite dilution the molar conductance can be interpreted in terms of such ionic contributions and that the contributions of an ion are independent of the other ion of the electrolyte. At infinite dilution, therefore, we wrote:

?° = v + λ°+ v- λ°- where 

λ°+ and λ°- are the molar ionic conductors at infinite dilution. Since the transference numbers give the fraction of the total current by each ion, i.e., the fraction of the total conductance that each contributes, we can write;

v+ λ°+ = t°+ ?°  and v- λ°- = t°- ?°  

where t°+ and t°- are the transference numbers extrapolated to infinite dilution. 

Ionic mobilities: consider a cell of the type used to introduce the concept of molar conductance. Such a cell consists of two electrodes 1m apart and of cross-section area A such that an amount of solution that contains 1 mol of electrolyte is held between the electrodes. For an applied voltage ∫, a current I will flow through the cell. These electrical quantities are related, since the conductance of such a cell is the molar conductance of the electrolyte, by:

I = ∫/R or I = ?∫

At infinite dilution the current can be attributed to the independent flow of positive and negative ions, and one can write:

I = ?°∫ = [v+ λ°+ + v- λ°- ] ∫ = v + λ°+ ∫ + v- λ°- ∫ = I+ + I-

   Related Questions in Chemistry

  • Q : Question based on lowering of vapour

    Choose the right answer from following. The relative lowering of vapour pressure produced by dissolving 71.5 g of a substance in 1000 g of water is 0.00713. The molecular weight of the substance will be:  (a) 18.0 (b) 342 (c) 60 (d) 180

    		•
  • Q : 6. 20 gm of hydrogen is present in 5

    6. 20 gm of hydrogen is present in 5 litre vessel. The molar concentration of hydrogen is

    		•
  • Q : Problem associated to vapour pressure

    Provide solution of this question. 60 gm of Urea (Mol. wt 60) was dissolved in 9.9 moles, of water. If the vapour pressure of pure water is P0 , the vapour pressure of solution is:(a) 0.10P0 (b) 1.10P0 (c) 0.90P0 (d) 0.99P0

    		•
  • Q : What are aliphatic amines and its

    In common system, the aliphatic amines are named by using prefix for alkyl group followed by the word amine.In case of mixed amines, the name of alkyl groups are arranged in alphabetical order. This is followed by the word amine. However, for simple secondary or tertiary amines anothe

    		•
  • Q : Theory of one dimensional motion For

    For motion in one dimension, the distribution of the molecules over quantum states, speeds, and energies can be deduced.Here we show that the energy of a macroscopic gas sample can be described on the basis of our knowledge of the quantum states allowed to

    		•
  • Q : How haloalkanes are prepared from

    Alkyl halides can be prepared from alkanes through substitution and from alkenes through addition of halogen acids or through allylic substitution.    From alkanesWhen alkanes are treated with halogens, chlo

    		•
  • Q : Explain Solid Compound Formation. In

    In some two component, solid liquid systems, a solid compound forms.In systems in which the components have an interaction for such other, a solid state compound of the two compounds of the two components can form.Formic acid and formaide form a solid state, one-to-one com

    		•
  • Q : Molarity of HCl solution 20 ml of HCL

    20 ml of HCL solution needs 19.85 ml of 0.01M NaOH solution for complete neutralization. Morality of the HCL solution is:  (i) 0.0099 (ii) 0.099 (iii) 0.99 (iv) 9.9 Choose the right answer from above.

    		•
  • Q : Procedure to judge that organic

    Describe briefly the procedure to judge that the given organic compound is pure or not?

    		•
  • Q : Problem on molarity-normality-molality

    Can someone please help me in getting through this problem. The solution ofAl2(SO4)3 d = 1.253gm/m comprise 22% salt by weight. The molarity, normality and molality of the solution is: (1) 0.805 M, 4.83 N, 0.825 M (2)

    		•