Q. Test for hydrocyanic acid?

Hydrocyanic acid is present as an impurity in synthetic ethyl isothiocyanate, which is employed to make the flavour of mustard oil more pungent. The method is based on the reaction of hydrocyanic acid on the picric acid paper, which acquires a red colour in the presence of that acid.

After learning about the different tests for assessment of the quality of fats and oils, let us now apply this knowledge in assessing the quality of a given sample of fats and oils in experiments 1-5.