Question

What reagent would distinguish between Ba²⁺ and Pb²⁺?

A) NaCl
B) Na₂S₂O₃
C) Na₂SO₄
D) NaNO₃

Answer 1

C) Na₂SO₄

Step-by-step explanation:

To distinguish between Ba²⁺ and Pb²⁺ ions, we can use a reagent called Na₂SO₄, which is sodium sulfate.

When Na₂SO₄ is added to a solution containing Ba²⁺ ions, it forms a white precipitate called barium sulfate (BaSO₄).

On the other hand, when Na₂SO₄ is added to a solution containing Pb²⁺ ions, it does not form a precipitate.

Answer 2

Na2SO4 (sodium sulfate) distinguishes between Ba2+ and Pb2+ by forming a precipitate only with Ba2+, resulting in BaSO4.

Step-by-step explanation:

The reagent that would distinguish between Ba²⁺ and Pb²⁺ ions is Na₂SO₄ (sodium sulfate). This is due to the fact that sodium sulfate will form a precipitate with the barium ion, resulting in an insoluble compound BaSO₄, whereas it will not form a precipitate with the lead ion under normal conditions. On the other hand, sodium chloride (NaCl) would react with the lead ion to form PbCl₂, which is a white precipitate, but it would not precipitate with the barium ion.