Question

State with equations what happens when borax is heated on a platinum wire loop and to the resulting transparent mass, a minute amount of CuO is added and the mixture is again heated first in the oxidising flame and then in the reducing flame of a Bunsen burner ?

Answer 1

"Sodium borate is also called as borax. It is one of the important forms of boron compound. Sodium tetraborate and disodium tetraborate are salt forms of boron.

Borax are white coloured crystals which are readily dissolved in water.

On heating strongly, borax loses "water of crystallization" to form colourless, "transparent glass" like "bead" made up of "sodium metaborate" and "boric anhydride."

The reaction is as follows.

$\begin{matrix} { Na }_{ 2 }{ B }_{ 4 }{ O }_{ 7 }.10{ H }_{ 2 }O \\ Borax \end{matrix}\quad \xrightarrow [\Delta]{ 10{ H }_{ 2 }O } \quad \quad { Na }_{ 2 }{ B }_{ 4 }{ O }_{ 7 }\quad \xrightarrow { \Delta} \quad \begin{matrix} 2{ NaBO }_{ 2 }\quad +\quad { B }_{ 2 }{ O }_{ 3 } \\ Transperent\quad Beads \end{matrix}$ "