Question

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

• A. A transparent white bead is formed.
• B. A bright pink 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 1

Answer: (C)

A blue coloured $Co(BO_{2})_{2}$ bead is formed.

Answer 2

: $\mathrm { Na } _ { 2 } \mathrm {~B} _ { 4 } \mathrm { O } _ { 7 } \cdot 10 \mathrm { H } _ { 2 } \mathrm { O } \xrightarrow { \Delta } \mathrm { Na } _ { 2 } \mathrm {~B} _ { 4 } \mathrm { O } _ { 7 } \xrightarrow { \Delta } 2 \mathrm { NaBO } _ { 2 } +$ $\mathrm { B } _ { 2 } \mathrm { O } _ { 3 }$ $B_{2}O_{3} + CoO \rightarrow \underset{\begin{aligned} & Cobaltmetaborate \\ & (Bluebead) \end{aligned}}{Co(BO_{2})_{2}}$