Question

The ksp for BaCrO₄ is 1.2x10⁻¹⁰. will BaCrO₄ precipitate when 10 ml of 1.0x10⁻⁵ m Ba(NO₃)₂ is mixed with 10 ml of 1.0×10⁻³ m K₂CrO₄?

Answer 1

When the concentrations of Ba2+ and CrO42- are calculated after mixing the two solutions, we find that the reaction quotient (Q) exceeds the Ksp of BaCrO4, indicating that a precipitate will form.

Step-by-step explanation:

The question asks whether BaCrO4 will precipitate when 10 ml of 1.0x10-5 M Ba(NO3)2 is mixed with 10 ml of 1.0x10-3 M K2CrO4. The solubility product constant (Ksp) of barium chromate (BaCrO4) is given as 1.2x10-10. To determine if a precipitate will form, one must compare the reaction quotient (Q) to the Ksp value.

First, calculate the concentrations of Ba2+ and CrO42- after mixing:

• [Ba2+] = (1.0x10-5 M * 10 ml) / (20 ml) = 5.0x10-6 M
• [CrO42-] = (1.0x10-3 M * 10 ml) / (20 ml) = 5.0x10-4 M

Now, calculate the reaction quotient (Q):

Q = [Ba2+][CrO42-] = (5.0x10-6 M) * (5.0x10-4 M) = 2.5x10-9

Compare Q to Ksp:

If Q > Ksp, a precipitate will form. In this case, Q (2.5x10-9) is greater than Ksp (1.2x10-10), so a precipitate of BaCrO4 will indeed form when the two solutions are mixed.