Question

Which of the following compounds is formed in borax bead test?

• A. Metaborate
• B. Tetraborate
• C. Triborate
• D. Orthoborate

Answer 1

The correct option is A Metaborate

Answer:- (A) Metaborate

On heating ,borax loses water of crystallisation and swells up to form fluffy mass. On further heating, it melts to give a clear liquid which solidifies to a transparent glossy bead consisting of sodium metaborate and boric unhydride.

${Na}_2{B}_4{O}_7.10H₂O\stackrel{△}{\to }{Na}_2{B}_4{O}_7\stackrel{△}{\to }\underset{\text{Sodium Metaborate}}{2NaB{O}_2}+B_2{O}_3$

Thus, Metaborate is formed.