experiment diffusion of NaCl in deionized water

1. Study of Diffusion
Prepared by-
Mahe Rukh
Student id- 1202036
Level-3 term-1
Department of chemical engineering

2. Presentation
outline
Objective
Theory of diffusion
Experimental
Procedure
Calculated data
Result
Discussion on result
ModificationsObserved data

3. Objectives
Measurement of liquid diffusion coefficient of
NaCl solution in deionized water
Observing effect of concentration on diffusion
coefficient
Exploring Fick’s law of diffusion

4. What is
diffusion?

5. Spraying Perfume

6. Higher concentration of perfume in adjacent area of spray
bottle

8. Perfume spreading throughout the
entire space

9. Perfume spreading throughout the
entire space
High
Concentration
Low
Concentratio
n
Concentration
gradient

10. What is
diffusion?
The net movement of particle from a
region of their higher concentration to a
region of their lower concentration down a
concentration gradient, as a result of their
random movement.

11. Diffusivity is affected by-
Temperature
Size of particles
Diffusion
mechanism
Concentration of
diffusing species
State of
matter

12. A. More steep
concentration
gradient
B. Less steep
concentration
gradient
A. Faster
rate of
diffusion
B. Slower
rate of
diffusion
Effect of concentration gradient on diffusivity

13. Fick’s law of diffusion
Where
D= diffusivity, cm2/s
J= rate of transfer per unit area of
section, mol/cm2.s
C= concentration of diffusing
substance
X= the space coordinate measured
normal to the section

14. Fick’s law of diffusion

15. Experimental setup

16. Experimental setup
used in the laboratory

17. Diffusion cell
Capillaries
Conductivity
probe
Conductivity
meter
Diffusion vessel
Magnetic stirrer
Bench
Stirrer bar

18. Observed data

19. Number of
observation
Reading from conductivity meter
1 M NaCl 4 M NaCl
Time (s) EC (µS) Time (min) EC (µS)
1 300 157.4 300 709.2
2 600 179.1 600 834.4
3 900 191.6 900 894.4
4 1200 199.8 1200 937.2
5 1500 207.2 1500 968.2
6 1800 212.8 1800 997.5
7 2100 217.3 2100 1018
8 2400 220.7 2400 1038

20. Calculated data

21. Experimental
values of diffusion
coefficient (cm2/s)
0.0225 3.96x10-5
0.1093 4.576x10-5

22. Graphical
representation

23. 1M solution 4M solution

24. Result

25. Diffusion co-efficient
for 1M NaCl solution
Diffusion co-efficient
for 4M NaCl solution
Theoretical
vaule
3.96x10-5 cm2/s 4.576 x10-5
cm2/s
1.611 x10-5
cm2/s

26. Temperature variation
Air bubbles in the capillaries of diffusion cell
Discussion
Mixture not being stirred well
1M and 4M solution not being prepared well
Problem in cleaning of diffusion cell

27. Modifications
Using porous plate
Using more than one conductivity
sensors at various depths of the solution
Minimum contact with the surrounding
should be checked

28. Thank you