Consider a solution containing dipolar molecules each having a positively-charge
ID: 558975 • Letter: C
Question
Consider a solution containing dipolar molecules each having a positively-charged head and a negatively-charged tail. In the absence of an electric field, the molecules point north (n), south (s), east (e), and west (w) with equal probabilities (distribution shown in Fig. 3a). A different probability distribution (shown in Fig. 3b), however, is found when a field is applied to the solution. 16 16 ne Fig. 3a (field absent)Fig. 3b (field present) a) Determine the direction in which the field has its most positive pole (the polarity of the field). b) In the absence of the field, what is the entropy of the system? c) In the presence of the field, what is the entropy of the system? d) Does the application of the field cause the system to become more ordered or disordered?Explanation / Answer
a) Since, most of the positive heads of the molecules are now pointing north, therefore it can b concluded that the north contains the negative pole. Hence field is from South to North.
b) in the absence of the field, the molecules have a freedom to move in whichever direction. Hence entropy is higher as randomness can b higher.
C) In the presence of field, molecules are arranged in a particular direction mainly, thus bringing order and hence entropy is decreased.
d) The application of the field brings order in the system as molecules are arranged majorly in a particular direction.