Discussion Forum



1)

 An aqueous solution of a mixture of two inorganic salts, when treated with dilute HCl, gave a precipitate (P) and the filtrate (Q). The precipitate  P was found to dissolve in hot water. The filtrate (Q) remained unchanged when treated with H2 S in a dilute mineral acid medium. However, it gave a precipitate (R)   with H2 S  in an ammonical medium. The precipitate R gave a coloured solution (S) when treated with H2O2 in an aqueous NaOH medium.

 The precipitate P contains


A) $Pb^{2+}$

B) $Hg^{2+}_{2}$

C) $Ag^{+}$

D) $Hg^{2+}$

Answer:

Option A

Explanation:

Plan PbCl2 is soluble in hot water. In an ammonical medium, cations of group III and IV may be precipitated as hydroxide or sulphide  and dissolved in H2O2 due to oxidation

A mixture of two inorganic salts

1252021758_c22.JPG

thus   P is Pb2+