Question

How will you obtain [PbCl₄]²⁻ from (PbNO₃)₂? Give the chemical equation for the reaction.

Answer 1

First, lead nitrate reacts with hydrochloric acid to form white precipitate of lead chloride:

\[\ce{Pb(NO3)2 + 2HCl → PbCl2 ↓ + 2HNO3}\]

On adding excess concentrated HCl, the precipitate dissolves to form tetrachloroplumbate(II):

\[\ce{PbCl2 + 2Cl− → [PbCl4]^{2-}}\]

Therefore, the required complex ion is [PbCl₄]²⁻.

This form is chemically clearer because it shows the formation of PbCl₂ first and then its conversion into the complex ion.