For the purpose of systematic qualitative analysis, cations are classified into various groups on the basisof their behaviour against some reagents. The group reagents used for the classification of most common cations are hydrochloric acid, hydrogen sulphide, ammonium hydroxide, and ammonium carbonate. Classification id based on wheather a certain reacts with these reagents by the formation of precipitates or not.
An aqueous solution contains `Hg^(2+),Hg_2^(2+),Pb^(2+)` and `Cd^(2+)`.The addition of 2 M HCl will precipitate :

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.