Preparation of Caustic alkali

Most of the students of Chemistry might have seen the preparation of Caustic Alkali in the Chemistry Laboratory. However, such preparation of caustic alkali was also carried out long ago. Let us see how our ancient India rishis did it.................................

Given below is a slokha from Susrutasamhita Sutrastanam 11 - 12  and its translation.................

Some well grown trees in the forest are cut into logs and piled in a place free from strong wind. Lime stone/scashell  should be placed on the piles and then set on a fire by stalks of dry plants. When all the wood is burnt out, the fire extinguished, the ashes of the logs and the burnt lime are collected and kept separate and dissolved in water. The extract of the ashes is then mixed with lime water to get the lye which is separated from the precipitate by filtration. The solution in concentrated to different extent by boiling and it is possible to get dilute, mild and caustic alkali.

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