What happen when a mixture of cobalt oxide and borax is heated in a flame on a loop of platinum wire?

Options

A. A transparent white heat is formed
B. A bright pind coloured `NaBO_(2)` bead is formed.
C. A blue coloured `Co(BO_(2))_(2)` bead is formed
D. A red coloured `CO(BO_(2))_(2)` bead is formed.

Answer

C

Explanation

`Na_(2)B_(4)O_(7).10H_(2) O overset(Delta)(to) Na_(2)B_(4) O_(7) overset(Delta)(to) 2NaBO_(2) + B_(2)O_(3)`
`B_(2)O_(3) + CoO to underset("Cobalt metaborate")underset(("blue bead"))(Co(BO_(2))_(2))`