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Explain borax bead test. |
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Answer» Solution :Borax bead test : On heating, borax FIRST loses water molecules and SWELLS up. On further heating it turns into a transparent liquid, which SOLIDIFIES in to glass like material known as borax bead. `Na_2B_4O_7 . 10H_2O oversetDeltato underset"Sodium metaborate"(Na_2B_4O_7) oversetDeltato underset"Boric anhydride"(2NaBO_2 + B_2O_3)` Sodium metaborate Boric anhydride The metaborates of many transition metals have characteristic colours and therefore, borax bead test can be used to identify them in the laboratory. For EXAMPLE, when borax is heated in a Bunsen burner flame with CoO on a loop of platinum wire, a blue COLOURED `Co(BO_2)_2` bead is formed. |
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