Question

Exactly 200 mL of 0.0040 M BaCl₂ are mixed with exactly 600 mL of 0.008 M K₂SO₄. Will a precipitate form? (Given: Kˢᵖ ​ of BaSO₄ = 1.1×10⁻¹¹)

A. QB. Q=Kˢᵖ ​, so there will be no precipitate.
C. Q>Kˢᵖ ​, so a precipitate will form.
D. Need more information to decide.

Answer 1

After mixing 200 mL of 0.0040 M BaCl₂ with 600 mL of 0.008 M K₂SO₄ and computing Q, it is concluded that Q < Ksp and thus no precipitate will form.

Step-by-step explanation:

When 200 mL of 0.0040 M BaCl₂ is mixed with 600 mL of 0.008 M K₂SO₄, to determine if a precipitate will form we need to calculate the ion product (Q). The reaction in question is the formation of barium sulfate (BaSO₄) from barium (Ba⁺²) and sulfate (SO⁴²⁺) ions. Q is computed as the product of the concentrations of these ions after mixing but before precipitation occurs.

This is compared to the solubility product constant, Ksp, for BaSO₄, which is given as 1.1×10⁻¹¹. If Q is greater than Ksp, a precipitate will form. After calculations, we find that Q = (2.9×10⁻⁴)(1.8×10⁻⁴) = 5.2×10⁻⁸. Since 5.2×10⁻⁸ is less than 1.1×10⁻¹¹, Q < Ksp and no precipitate will form.