When borax is heated... |The p-Block Elements|JEE-Main 2022

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JEE MAIN 2022

29-07-2022 S2

Question

When borax is heated with CoO on a platinum loop, blue coloured bead formed is largely due to:

Select the correct option:

$\mathrm{B}_2 \mathrm{O}_3$

$\mathrm{Co}\left(\mathrm{BO}_2\right)_2$

$\mathrm{CoB}_4 \mathrm{O}_7$

$\mathrm{Co}\left[\mathrm{B}_4 \mathrm{O}_5(\mathrm{OH})_4\right]$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

$$ \begin{aligned} & \mathrm{Na}_2 \mathrm{~B}_4 \mathrm{O}_7 10 \mathrm{H}_2 \mathrm{O} \xrightarrow{\Delta} \mathrm{Na}_2 \mathrm{~B}_4 \mathrm{O}_7+10 \mathrm{H}_2 \mathrm{O} \\ & \mathrm{Na}_2 \mathrm{~B}_4 \mathrm{O}_7 \xrightarrow{\Delta} 2 \mathrm{NaBO}_2 \text { (sodium metaborate) }+\mathrm{B}_2 \mathrm{O}_3 \\ & \mathrm{~B}_2 \mathrm{O}_3+\mathrm{CoO} \rightarrow \mathrm{Co}\left(\mathrm{BO}_2\right)_2 \text { (cobalt (II) meta borate) } \end{aligned} $$ Blue Bead

Question Tags

JEE Main

Chemistry

Easy

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