Answer:
The BaSO₄ precipitates as a solid.
Explanation:
In order to determine the precipitation, we need to look at the reactants, we have: Ba(NO₃)₂ and Li₂SO₄
Salts from nitrate are all soluble and sulfates can make precipitate if they react to elements from group 2. (Solubility rules) So this reaction, has a precipitate but we can predict it, if we look at the reaction and we take acount the Kps:
Ba(NO₃)₂ (aq) + Li₂SO₄ (aq) → 2LiNO₃ (aq) + BaSO₄ (s) ↓
Let's find out the moles of each ion:
Ba(NO₃)₂ (aq) → Ba²⁺ (aq) + 2NO₃⁻ (aq)
0.8 L . 0.0002 M = 1.6×10⁻⁴ moles. These are the moles of Ba²⁺ in 1 L of solution, so [Ba²⁺] = 1.6×10⁻⁴ M
Li₂SO₄ (aq) → 2Li⁺ (aq) + SO₄⁻² (aq)
0.2 L . 0.0005 M = 1×10⁻⁴ M. These are the moles of sulfate, in 1 L of solution so [SO₄⁻²] = 1×10⁻⁴ M
BaSO₄ (s) ⇆ Ba²⁺ (aq) + SO₄⁻² (aq) Kps = 1.08×10⁻¹⁰
We need to compare Kps to [ Ba²⁺] . [SO₄⁻²]
[ Ba²⁺] . [SO₄⁻²] = 1.6 ×10⁻⁸ > Kps → Precipitate.
If [Ba²⁺] . [SO₄⁻²] = Kps → Solution is saturated
If [ Ba²⁺] . [SO₄⁻²] < Kps → There is no precipitate formed, or if it is formed, it will be quickly dissolved to reach saturation.
