JEE Advanced · 2013 · 02 Jun 2013 · Paper 2 · Practical and Analytical Chemistry

An aqueous solution of a mixture of two inorganic salts, when treated with dilute

H C l

, gave a precipitate

(P)

and a filtrate

(Q)

. The precipitate

P

was found to dissolve in hot water. The filtrate

(Q)

remained unchanged, when treated with

H_{2} S

in a dilute mineral acid medium. However, it gave a precipitate

(R)

with

H_{2} S

in an ammoniacal medium. The precipitate

R

gave a coloured solution

(S)

, when treated with

H_{2} O_{2}

in an aqueous

N a O H

medium.

The precipitate

P

contains

Answer: (A)

Solution

The precipitate

P

forms with dilute HCl and dissolves in hot water. This is characteristic of

PbCl_{2}

, which is sparingly soluble in cold water but soluble in hot water.

Pb^{2 +} + 2 HCl \to PbCl_{2} ↓ + 2 H^{+}

AgCl

and

Hg_{2} Cl_{2}

do not dissolve in hot water, so the precipitate contains

Pb^{2 +}

JEE Advanced · 2013 · 02 Jun 2013 · Paper 2 · Single correct option