How do you visualize colourless compounds after separation in TLC and

1.	How do you visualize colourless compounds after separation in TLC and paper chromatography
Answer» 1) Visualization of colored compounds is simple the spots can be directly observed after development. 2) Because most compounds are colorless however, a visualization method is needed. 3) The silica gel on the TLC plate is impregnated with a fluorescent material that glows under ultraviolet (UV) light. 4) A spot will interfere with the fluorescence and appear as a dark spot on a glowing background. 5) While under the UV light, the spots can be outlined with a pencil to mark their locations. 6) A second method of visualization is accomplished by placing the plate into IODINE vapors for a few minutes. 7) Most organic compounds will form a dark-colored complex with iodine. 8) It is good practice to use at LEAST two visualization techniques in case a COMPOUND does not show up with one particular method.

Discussion