Question

Borax-bead test can be used to identify following ions :

• A. ${Ca}^{2+}$
• B. ${Cr}^{3+}$
• C. ${Mn}^{2+}$
• D. ${Cu}^{2+}$

Answer 1

Answer: (B), (C), (D)

The correct options are
B ${Cr}^{3+}$
C ${Mn}^{2+}$
D ${Cu}^{2+}$

Borax-bead test can be used to identify coloured ions such as ${Cr}^{3+},{Mn}^{2+},{Cu}^{2+}$.
A transparent bead of borax is first prepared when borax is heated on to a platinum wire loop and then the salt that is required to be analysed will be placed on the bead.
$N{a}_2{B}_4{O}_7.10H_{2}0+Heat\to 2NaB{O}_2+B_2{O}_2+10H_{2}0$
Borax Transparent bead
Thus, we can identify the radical by the characteristic colour.(Refer table given)