When small amount of ${\mathrm{SnCl}}_2$ is added to a solution of ${\mathrm{Hg}}^{2+}\text{ ions, }$ a silky white precipitate is obtained. The silky white precipitate is due to the formation of:

When small amount of ${\mathrm{SnCl}}_2$ is added to a solution of ${\mathrm{Hg}}^{2+}\text{ ions, }$ a silky white precipitate is obtained. The silky white precipitate is due to the formation of ${\mathrm{Hg}}_2{\mathrm{Cl}}_2$.

${\mathrm{SnCl}}_2+{\mathrm{Hg}}^{+2}⟶\underset{(\mathrm{white} \mathrm{ppt})}{{\mathrm{Hg}}_2{\mathrm{Cl}}_2}$

Thus, the option A is correct.