Q. Test for the presence of argemone oil?

This test helps to detect the presence of argemone oil. Argemone mexicana  is the plant, which yields seeds of this oil.  The seeds are very small similar to black mustard seeds but has striations and pointed end. Oil extracted from these seeds is toxic in nature and results in epidemic dropsy. These toxic substances are soluble in HCl and with Ferric Chloride (FeCl3) they are precipitated out. These precipitates contain needle-shaped crystals and can be observed microscopically.