Debye huckel limiting law mathematical represented

1. Presentation
Debye huckel limiting law
Ameer
presented by Hamza
Ghazi University Dera Ghazi
Khan

2. Explain
• peter Debye and Erich Huckel
• 1923 Quantitative γ± of S.E
• L.L.E = log �+
_
=− �(�+�−) �
• Dilute = S.E

3. Assumptions
(1) 100 % Dissociation
(2) Dilute (0.01m)
(3) Two Forces
(a) Asymetric force
(b) viscous∖ Drag force

4. ( 5) Each ion is
surrounded by I.A
(4) F= �1�2 ∕ �2

5. Energy of the I.A is electrical energy of a
charge body that is the work expended in the
process of changing in the half of the product
it is charge and potential.
�� =
1
2
(charge)(potential)
∈ �� =charge
-
��∈�
�
= potential
��=
�
�
∈ ��(-���
∈�
)

6. • ��=
−��2∈2�
2�
• for 1g ion
��
=
−���2∈2�
2� (1)
chemical potential of
ion in ideal solution
��=��
∙
+ ������

7. • For non ideal solution
• ��=��
∙
+ ������ (2)
��=��
��
putting the value of �� in
equation (2)
��=��
∙
+RTln����
RTln multiply by �� and ��
��=��
∙
+RTln��+RTln�� (3)

8. • Difference between equation (2) and (3)
• Free energy=RTln�� (4)
• common equation 1 and 4
• RTln��=-
���� �
��
��
• ln��= - NZ�2
�2
� ∕ 2DRT

11. • log��=-0.509��
2
�
• �� for invidual ion cant be calculated
• -log�_
+
=0.509�+�− �
• This Debye huckel limiting law equation.
• (D.s)

12. • Deviation (� ↑,�+�− ↑)
• verification
• -log=�−
+
=0.509�+�− �
• y=mx

14. • ��+
��−
��+2
��2−1
��+3
��3−1
• m=0.509(1× 1)
• m=0.509(2× 1)
• m=0.509(3× 1)

15. Thank you