Question

Which of the following pairs of aqueous solutions will form a precipitate when mixed?

Answer 1

Answer:

The correct answer is A) Pb(C₂H₃O₂)₂ + Li₂SO₄

Explanation:

• All salts of Na, K and ammonium are soluble.
• All nitrates are soluble.
• All chlorides are soluble, with the exception of AgCl, Hg₂Cl₂, PbCl₂ and CuCl.
• All sulfates are soluble, with the exception of CaSO₄, SrSO₄, BaSO₄, PbSO₄, HgSO₄, Hg₂SO₄ and Ag₂SO₄.
• All hydroxides are poorly soluble, with the exception of alkaline hydroxides, Sr(OH)₂, Ba(OH)₂ and NH4(OH)
• All carbonates are poorly soluble, with the exception of alkaline carbonates and ammonium carbonate.
• All sulfides are poorly soluble, with the exception of alkaline sulfides, alkaline earth sulfides, and ammonium sulfide.

The reaction A is:

Pb(C₂H₃O₂)₂ + Li₂SO₄ ⇒PbSO₄ + 2 LiC₂H₃O₂

Lead sulfate is a slightly soluble solid, therefore it precipitates.