Division 6.3.3

After completely evaporating the development solvent, place the plate for two to three minutes in an atmosphere of chlorine vapour, which is produced by pouring about 100 ml of hydrochloric acid (4.9) over about 2 g of potassium permanganate (4.8) in a closed vessel. Remove the excess chlorine by heating the plate to 100 ^oC for five minutes. Then spray the plate with the reagent (4.10).