Question

What is borax bead? What is it composed of??

Answer 1

Borax Bead: It is a colourless transparent glass like bead which is a mixture of sodium metaborate(NaBO2) and boric anhydride (B2O3). 

When, borax Na2B4O7 .10H2O is heated under bunsen flame, it looses its water of crystallization and forms a colourless transparent  glassy bead called as borax bead which is a mixture of sodium metaborate and boric anhydride as;

 Na2B4O7 .10H2O -----(Heat)--->  Na2B4O7 --(heat)-->[ 2NaBO2 + B2O3 ] a glassy bead mixture

This mixture [ 2NaBO2 + B2O3 ] is called as borax bead. It is used to test the presence of certain metals.

Answer 2

Borax beads is a mixture of boron oxide (B2O3)and sodium metaborate (NaBO2) together.

Explanation:

• Powdered borax Na2B4O7 • 10H2O, when heated violently with a Bunsen burner flame, forms colorless and transparent glass beads called borax.
• Beads are composed of sodium metaborate (NaBO2) and boron oxide (B2O3).
• Borax beads can be used to detect metals.
• The Borax beads test is performed with cobalt salts, copper salts, and nickel salts. Borax naturally occurs in evaporated sediments formed by repeated seasonal lake evaporations.
• From  boric acid:
• Borax is made by boiling boric acid with soda ash.
• When the solution cools, the borax separates. It is a white crystalline solid that is sparingly soluble in cold water but sparingly soluble in hot water.
• The aqueous solution of borax becomes alkaline by hydrolysis.

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