A sodium ion, Na+, has a charge of +e = 1.602 × 10-19 C and a water molecule has a dipole moment of 1.85 D, where 1 D = 1

Debye = 3.336 x 10-30 Cm. (a) Derive an expression for the potential energy of the system when the dipole is a distance r from the ion and makes an angle 0 with the connecting line. (b) Determine the angles 0min and 0max Where the potential energy of the system is at a minimum and maximum, respectively. (c) Compare the potential energy of the system for the angle 0min and a distance r = 0.25 nm with the thermal energy kBT, where kB is Boltzmann's constant, fora temperature T of 300 K.