Chemistry - Salt Analysis Question with Solution | TestHub

Question Explanation:

Group IIA sulfides are $\mathrm{MS}(\mathrm{CuS},\mathrm{CdS})$ or ${\mathrm{M}}_2{\mathrm{S}}_3\left({\mathrm{Bi}}_2{\mathrm{S}}_3\right),{\mathrm{M}}_2{\mathrm{S}}_2\left({\mathrm{Hg}}_2{\mathrm{S}}_2\right)$ or ${\mathrm{MS}}_2\left({\mathrm{SnS}}_2\right)$. Concept:

Formulae of Group II Sulfides.

Solution:

The Group II cations have varying valencies. ${\mathrm{Hg}}^{2+},{\mathrm{Cu}}^{2+},{\mathrm{Cd}}^{2+},{\mathrm{Pb}}^{2+}$ precipitate as MS (or ${\mathrm{M}}_2\mathrm{S}$ in the case of ${\mathrm{Hg}}_2^{2+}$ ).

${\mathrm{Bi}}^{3+}$ precipitates as ${\mathrm{M}}_2{\mathrm{S}}_3\left({\mathrm{Bi}}_2{\mathrm{S}}_3\right)$.

${\mathrm{As}}_2{\mathrm{S}}_3,{\mathrm{Sb}}_2{\mathrm{S}}_3,{\mathrm{Bi}}_2{\mathrm{S}}_3\Rightarrow {\mathrm{M}}_2{\mathrm{S}}_3$

$\mathrm{HgS},\mathrm{PbS},\mathrm{CdS},\mathrm{CuS}\Rightarrow \mathrm{MS}$

${\mathrm{SnS}}_2\Rightarrow {\mathrm{MS}}_2$

Final Answer: Options (A, C & D)