List different test for identification:
1) Dilution Test -
2) Dye Test-
3) Conductivity Test-
4)Fluorescence Test:
5)Cobalt Chloride Test:
Explanation of any one.
1) Dilution Test -
Emulsion diluted with water i)Emulsion remains stable then it is o/w emulsion
ii)Emulsion break it is w/o emulsion
Emulsion diluted with oil i)Emulsion remains stable then it is w/o emulsion
ii)Emulsion break it is o/w emulsion
2) Dye Test-
Emulsion diluted with scarlet red dye
i)Dispersed globules appear red & background is colourless then it is o/w type
ii) Dispersed globules appear colourless & back ground is red then it is w/o type.
3) Conductivity TestThis type of emulsion show bulb glowing on passing electric current.
If bulb glow the emulsion is o/w type
If bulb does not glow the emulsion is w/o type
3) Fluorescence Test:
If an emulsion on exposure to ultra-violet radiations shows continuous
fluorescence under UV light, then it is w/o type
If it shows only spotty fluorescence, then it is o/w type.
5) Cobalt Chloride Test:
When a filter paper soaked in cobalt chloride solution is dipped in to an emulsion
and dried, it turns from blue to pink, indicating that the emulsion is o/w type.