Preparation of potassium carbonate from wood ashes

In this experiment, a classic preparation method is proposed for potassium carbonate from wood ash. The salt crystals that are formed as a result of the preparation procedure described within the experiment are of potassium carbonate; these can be subjected to a flame test, which give the characteristic violet colouring of potassium ions. The presence of sodium ions can mask the purple colouring, therefore you must proceed with the observation through a cobalt glass. Then you can proceed with testing with a universal litmus indicator which identifies the distinctly alkaline feature of salt. Finally, the presence of carbonate can be noted by treating some crystals with hydrochloric acid; you can see the classical effervescence due to the formation of carbon dioxide. Having discovered that a strong alkaline potassium compound was obtained from wood ash, you can understand why for centuries lye, produced by boiling wood ash, was the best laundry detergent. More generally, one can understand why wood ash has always been considered an excellent potassium fertiliser. Potassium, in fact, is one of the three elements needed in relatively large amounts (megaelements) to ensure the germination, growth and fruiting of plants. The other megaelements are phosphorus and nitrogen to which calcium is added, for some soils. Trace elements (copper, cobalt, boron, iron, etc.) are, on the other hand, essential for plants in small quantities to form enzymes