Saponification

[Sparcod]

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Hi. I'd like some questions answered.

1. How would saponification be demonstrated in a school lab. Which materials would be used to start off with? (Is it ok to have olive oil and NaOH?)

Also, how do you extract it? (with NaCl to salt out and ethanol to remove glycerol?)

2. What's an emulsion and how does that work?

3. How are membrane and diaphragms different in terms of structure?


Thanks for all help.

[frangipane]

I can help you with the third one:

Diaphram cell and membrane cell have identical structures except;
the "diaphram" is made of asbestos whilst the "membrane" is made of Polytetrafluoroethene-a cation exchange substance. This lets the Na+ through to the cathode but repels the Cl- and OH- so they don't come into contact and produce ClO-
Hence the membrane produces higher purity NaOH without the Environmental hazard of Asbestos losses.

[Sparcod]

OK. Makes sense. Still worried about the saponification q's.

[Petinga]

Aim: Production of soap via saponification
Method:
1. palce 5ml of castor oil with 25ml of 25%sodium hydroxide into a large beaker.
2.Place beaker on hotplate and gfenbtly boil for 30 minutes at 34 degress
3.Allow to cool for further 10minutes then add small amount of sodium chloiride acasingf soap to be ppt out as curds. stir for 2o minutes.
4. filter soap curds using water pump and rinse with distilled water on filter paper
simple as that. thats all ya need to know sparcod. Glycerol is not separated from salt solution in classroom, only in industry.

An emulsion is the dispersion of small droplets of one liquid in another liquid. neither liquid dissolves in the other. An examplke of an emulsion is oil in water. when oil is added to water and skaen, the oil droplete that form are unstable and quickly combine to form a layer that folats above water. hjowevwer when soap an emulsififer is added, oil is trapped in stabkliside fropletes due to hyrdophobic tail of soap dissolving in oila n charged heads clustering on surface resulting in stabilisation due to electrostatic repulsion of charge headsg grouops.