Question

Colorless salt (X)$\stackrel{\Delta }{\to }$(Y)$\stackrel{C{u}^{2+}\Delta }{\to }$ Colored bead (Z);

(X) can be :

• A. borax
• B. microcosmic salt
• C. copper sulphate
• D. none of these

Answer 1

Answer: (A), (B)

The correct options are
A borax
B microcosmic salt


$N{a}_2{B}_4{O}_7.10H_{2}O\to N{a}_2{B}_4{O}_7\to 2NaB{O}_2+B_2{O}_3$
$-10H_{2}O$ Borax bead

This glassy bead gives different coloured beads with ions such as $N{i}^{2+},C{o}^{2+},C{r}^{3+}$ etc. The salts containing these ions are heated to form oxides which form coloured meta borates with boron oxide. This test is called borax bead test
$CuO+B_2{O}_3\to Cu(B{O}_2{)}_2$

Cupric meta borate(blue)

Same for the microcosmic salt, it also gives the same results on heating.

$Microcosmicsalt$ is a salt found in urine with the formula $Na\left(N{H}_4\right)HP{O}_4$. It is left behind in the residues after extracting the urea from dried urine crystals with alcohol. In the mineral form, microcosmic salt is called stercorite.
Option A and B are correct.