The chemical formula of borax is .

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 03 Dec 2022 Shift 1)

Answer 1

The correct answer is Na2B4O7.10H2O.

Key Points

Borax is the sodium salt of boric acid.
Chemical formula:- Na2B4O7.10H2O
Borax occurs naturally as Tincal (suhaga) in certain dried-up lakes of India, Tibet, Srilanka and the USA. It contains about 55% borax.
Tincal is the crude form of borax, and it contains many impurities. Borax is also found as tincal in Ceylon, Tibet and California.
In Tibet, tincal is used as a cleaning product by the native tribes.

Important Points

Preparation of Borax from Colemanite (Ca2B6O11)

In this method, the colemanite mineral is finely powdered and boiled with a solution of sodium carbonate solution. As a result, borax and sodium metaborate is formed.
The white precipitate of calcium carbonate obtained during the reaction is removed by the process of filtration, and the solution upon concentration and then cooling gives the pure crystals of borax. By passing carbon dioxide gas through the sodium metaborate, which is present in the mother liquor, it can be converted to borax.

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Preparation of Borax from Tincal

Tincal can be transformed into borax by being dissolved in boiling water. The resulting solution is filtered to get rid of any insoluble contaminants like sand, clay, etc.
The resulting solution can be concentrated to get the pure crystals of borax.

Preparation of Borax from Boric acid

Boric acid and sodium carbonate can be combined to create borax in modest quantities.

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