When H 2 S is passed in the mixture of Pb ( NO 3 ) 2 + Excess of KCl in Aq. solution, colour of ppt. is :

Question

When H 2 ​ S is passed in the mixture of Pb ( NO 3 ​ ) 2 ​ + Excess of KCl in Aq. solution, colour of ppt. is :

TestHub · Accepted Answer

Pb(NO₃)₂ reacts with excess KCl to form a complex chloro-plumbate ion. When H₂S gas is passed through this solution, lead sulfide does not separate as the usual black precipitate. Instead, due to the presence of excess chloride ions, a red-colored precipitate of PbS·PbCl₂ (chlorosulfide of lead) is formed. Therefore, the precipitate obtained is red in color**.

$P b^{2 +} + H_{2} S \to P b S ↓$

In excess Cl⁻ medium:

$P b S + P b C l_{2} \to P b S ∙ P b C l_{2} (re d ppt)$

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