This document describes Lassaigne's test to detect nitrogen, sulfur, and halogens in organic compounds. Sodium fusion is used to convert elements in organic samples to soluble sodium salts. Tests are then performed on the fusion extract solution. Nitrogen is detected using ferrous sulfate and ferric chloride to form a Prussian blue or green precipitate/color. Sulfur is detected using sodium nitroprusside to form a violet color or lead acetate to form a black precipitate. Halogens like chlorine, bromine, and iodine are detected using silver nitrate to form characteristic precipitate colors soluble in ammonium hydroxide. The document provides procedures and expected observations for each elemental