Page 280 - MODERN ELECTROCHEMISTRY

216 CHAPTER 2

25. Calculate the change of solubility of 2,4-dinitrophenol in water due to primary
solvation when 0.1 M NaCl is added to the solution and the solvation number
of NaCl is assumed to be 5. (Kim)

26. Calculate the change of the solubility of ethyl ether (dielectric constant, 4,3;
density, in water due to the secondary solvation shell when 1 M
of NaCl is added to the solution
(Kim)

27. Show that the electrostatic interaction potential energy between two charges
and can be represented by the nonconventional although widely used
equation

where areexpressedinelectronic chargeunits, isthedistancebetween
the charges expressed in Å, is the relative dielectric constant of the medium,
and E is given in units of kcal/mol. What is the Coulombic interaction between
a proton and electron by 1 Å in vacuum? (Contractor)

28. (a) has an ionic radius of 60 pm. Calculate the work of charging the lithium
ion in vacuum, (b) Repeat the calculation for whose ionic radius is 181 pm.
(c) Calculate the work of charging surrounded by bulk water with a relative
dielectric constant of 80 at 293 K. (Contractor)

29. A positive charge of and a negative charge of are separated by 53 pm.
Calculate their dipole moment. (Contractor)

30. Calculate the effectivemoment that a gas dipole of water exhibits in the direction
of an external field of when subject to electrical orienting and thermal
randomizing forces at 25 °C. The dipole moment ofwater
(Contractor)

31. Estimate the average moment of a dipole cluster of water subject to an external
electric field of Assume the average of the cosine of the angles
between the dipole moment of the central water molecule and those of its bonded
neighbors is 1/3 at 298 K. (Contractor)

32. For liquid water, the relative dielectric constant at 25 °C is 78. Calculate its
deformation polarizability at this temperature if there are moles of defor-
*
mable molecules per unit volume. Use the average of the cosines of the angles

*
The deformable molecules are taken, in this problem to be less than the total number.