Easy MCQ +4 / -1 PYQ · JEE Mains 2023

During the borax bead test with $\mathrm{CuSO_4}$, a blue green colour of the bead was observed in oxidising flame due to the formation of :

  1. A CuO
  2. B Cu(BO$_2)_2$ Correct answer
  3. C Cu$_3$B$_2$
  4. D Cu

Solution

Blue green colour is due to formation of $\mathrm{Cu}\left(\mathrm{BO}_{2}\right)_{2}$ <br/><br/> $\mathrm{CuSO}_{4} \stackrel{\Delta}{\longrightarrow} \mathrm{CuO}+\mathrm{SO}_{3}$ <br/><br/> $\mathrm{CuO}+\mathrm{B}_{2} \mathrm{O}_{3} \rightarrow \mathrm{Cu}\left(\mathrm{BO}_{2}\right)_{2}$

About this question

Subject: Chemistry · Chapter: p-Block Elements · Topic: Group 13: Boron Family

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