Explain Borax bead test with suitable example.

Explanation

Borax Bead Test : This test is useful for the identification of coloured metal radicals in qualitative analysis. On heating, borax swells into a white, opaque mass of anhydrous sodium tetraborate . When it fused, borax glass is obtained. This contains sodium metaborate and `B_(2)O_(3)` . The boric anhydride combines with metal oxides to form metal metaborates as coloured beads. The reactions are as follows.
`underset("Borax")(Na_(2)B_(4))O_(7). 10H_(2)O to Na_(2)B_(4)O_(7)overset("fused")(to)`
`(2NaBO_(2)+B_(2)O_(3))/("Borax glass")`
`B_(2)O_(3)+CoO underset("Cobalt Metaborate(Blue bead)")(to Co(BO_(2))_(2))`