Saponification value of an oil

5 g of the sample is weighed into a conical flask and 50 ml of 0.5N alcoholic potassium hydroxide solution is added to it. The contents are boiled under reflux for 2 h. After cooling the excess alkali is back-titrated against 0.5N HCl using Methyl Orange as an indicator. A blank is also run (without tallow sample). 

The solution preserved after the determination of saponification value is extracted with petroleum ether, evaporated and dried in an oven. After cooling the residue is weighed. 

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