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

Hint: The sticklac extracted is smashed to reduce impurities and sieved. In order to remove insect pieces and other materials, the sieved surface is then cleaned repeatedly. Seedlac is the resulting product.

Complete answer:
Lac is a viscous secretion derived from various lacca insect species, with Laccifer lacca being the most widely cultivated. When a stick with the eggs or the broodlac are prepared to hatch, the planting starts. The brood lac stick is fixed to the tree that needs to be riddled. The lac insects colonise and emit a resinous material from the leaves of the host trees or infested trees. These host trees' roots are removed and later collected as sticklac.
Ber and Kusum, Dhak, are the two typical host trees that provide the strong yield of lac.

The raw lac is purified as follows—
- In an aqueous alkaline solution with a typical cation concentration, the raw lac is retained in order to make the lac salt of the alkali cation insoluble within this solution. In an alkaline solution, the dyes and other particulates are soluble.
- The resulting mixture is in the insoluble level of the lac resin and a significant majority of the particulates are in the solution.
- The insoluble resin salt that is treated with a fresh aqueous solution is isolated from the fluid by a filtration technique.

Note: Lac is harvested by chopping the sticklac-holding tree roots. The insects are preserved in the sticklac as dye is created and the colour of the dye derives from the insects instead of their resin. Exposure to the sun will destroy them.