Question

Tribal people from india have a great contribution in production of lac. But it needs certain trees. Name at least two such trees which give good yield of lac. How is raw lac purified?

Answer 1

• Lac is a resinous secretion obtained from different of species of lac insects, the most commonly cultivated is Laccifer lacca.
  
• The cultivation begins when a stick with the broodlac or the eggs are ready to hatch.
• The stick with broodlac is tied to the tree which is to be infested.
• The lac insects colonize the branches of the infested trees or the host trees and secrete a resinous substance. The branches these host trees are cut and later harvested as sticklac.
• In India, the most common host trees which give a good yield of lac are:- Dhak, Ber and Kusum.
• The purification of raw lac is as follows:-

1) The raw lac is suspended into an aqueous alkaline solution having a common cation concentration so that the lac salt of the alkali cation becomes insoluble in that solution.

2) The dyes and other impurities are soluble in the alkaline solution.

3) The resultant mixture the lac resin is in the insoluble phase and a large part of the impurities are in the solution.

4) The insoluble resin salt is separated from the solution by filtration process which is washed with a fresh aqueous solution.