Reactants:
All reactants should be of known analytical quality; the water used must be distilled or
of equivalent purity.
Diethyl ether-ethanol at 95% (V/V), mix 1-3 in volume.
solution of NaOH titrant 0.1 N or 0.5 N if necessary. The exact value of the sodium
hydroxide solution must be known and verified before use.
phenolphthalein, ethanolic solution at 1%
Equipment:
analytical scales
flask with a capacity of 250 ml
burette that has a capacity of 50 ml graduated in 0.05 ml.
Procedure:
Substance to analyse: take approximately 5 g of the substance.
By shaking, titrate, with the sodium hydroxide solution of 0,1N until the indicator
changes colour (pink colour of phenolphthalein lingering for at least 10 seconds).
Expression of results:
The acidity expressed as % in mass is equal to: v*c*M *100
1000*m
Where:
V= volume in ml of known titre of sodium hydroxide used
c= the exact concentration of the known titre of sodium hydroxide solution used
M= the molecular weight of oleic acid (282)
m= the weight in grams of the substance analysed
Analysis of the olive oil carried out with the students from 2AG, 2AA, 2AB Forms.
https://www.youtube.com/watch?time_continue=17&v=EYS3VTaznd8
The teachers:
Mr Ceneri, Mrs Gabellieri, Mrs Pellegrini.