Cations are classified into varius group on the basis of their behaviour against some reagents .The group reagent used for the classifaction of most common cation are `HCI,H_(2)S,NH_(4)OH,(NH_(4))_(2)CO_(3)` Classification is based on whether a cation reacts with these reagents by the formation of precipitates or not .
An aqueous solution contain `Hg^(2+),Hg_(2)^(2+),Pb^(2+)`.THe addition of `2M HCI` will procipitate.

Options

A. `HgCl_2` only
B. `PbCl_2` only
C. `PbCl_2 and Hg_2Cl_2`
D. `PbCl_2 and CdCl_2`

Answer

C

Explanation

2M HCl is group reagents for group `I^(st)` cations. `PbCl_2 and Hg_2Cl_2` will get precipitate, as their solubility products `(K_(sp))` are less than that of other radicals.