1. Paper Chromatography and Separating immiscible liquids
E. Haniff

2. Objectives
Separate a mixture of different solutions using a given solvent (by difference of solubilities)
Separate a mixture of immiscible liquids

3. What are immiscible liquids?
Immiscible liquids are two liquids which cannot be dissolved in one another
They form two distinct layers

4. Separating immiscible liquids

5. Title: Separation of two immiscible liquids
Aim: To separate a mixture of oil and water
Apparatus and materials: Separating funnel with tap, water, oil and 3 containers

6. Diagram:

7. Method The apparatus was set up as shown in the diagram
The denser liquid at the bottom of the separating funnel was withdrawn through the tap and collected in a container
The container was then replaced with another and a small quantity of liquid was withdrawn (a mixture of the two right after the denser liquid was withdrawn

8. Method continued…
The container was then replaced again and the less dense liquid was allowed to run out and was collected.
Observations were noted

9. Observations Two separate layers were formed in the separating funnel.
The oil was seen at the top layer and the water at the bottom layer

10. Discussion
The separation of two immiscible liquids is based on the principle that the two liquids do not mix and form two distinct layers
The less dense liquid was the oil, which formed the top layer
The denser liquid was the water which formed the bottom layer and was withdrawn first, allowing the separation of the two liquids

11. Conclusion
The mixture of oil and water was separated using a separating funnel
Oil and water are immiscible liquids because they do not dissolve one another

12. Application….
The principle of immiscibility of liquids in some solvents is used in solvent extraction
Solvent extraction is used to separate a component from a mixture by using two solvents.
Two conditions have to be met:
The component must be more soluble in one solvent than in the other
The two solvents must be immiscible

13. For example…pg 75 To compare the solubility of iodine in two solvents
Iodine is dissolved in water
The water is mixed with 1,1,1-trichloroethane
The iodine goes into this solvent and the water can be drained off in a separating funnel

14. Another example

15. Uses of solvent extraction
Good for removing organic molecules from water
For example caffeine from tea or coffee.
Caffeine is an organic compound which is more soluble in an organic solvent which is immiscible with water.(Dichloromethane)

16. Title: Paper Chromatography
Aim: To separate the components of screened methyl orange
Apparatus and materials: filter paper, beaker, capillary tube, test tube, screened methyl orange

17. Diagram:

18. Method:
To a strip of filter paper, a capillary tube was used to place a small drop of methyl orange, close to the base of the paper
A small volume of water was placed in a test tube or beaker
The strip of filter paper was suspended so that it barely touched the solvent

19. Method:
It was left to stand for a while
Observations were recorded

20. Observations The liquid moved up the filter paper
Distinct colours could be seen
The colour that moved the furthest up the filter paper was…….

21. Observations

22. Discussion
Chromatography is a technique that uses a stationary phase and a mobile phase
The stationary phase is the filter paper in paper chromatography
The mobile phase is the solvent that moves up the paper
Chromatography can be used to separate minute quantities of substances.

23. Discussion
Separation of the different components occurs because each substance is soluble to different extents in the chosen solvent (the mobile phase)
The more soluble component travels the furthest up the filter paper and the least soluble remains closer to the base
Two colours were seen in screened methyl orange: two dyes a blue and a yellow

24. Conclusion
Screened methyl orange contains two components: a blue dye and a yellow dye
The more soluble component appeared blue in colour
The blue dye was more soluble in water

25. Applications of chromatography
Testing for trace contaminants in the environment
Monitoring water quality and air quality
Analyzing pure samples for trace contaminants (pharmaceutical industry)
Quality control in food industry