Will Mixing CaCl2 and NaOH Solutions Form a Precipitate?

[proskier]

Help please!

Here's the question I'm having problems with:

The solubility product of calcium hydroxide, Ca(OH)2, is 7.9 x 10^-6 at 25 degrees celcius. Will a precipitate form when 100mL of 0.10 mol/L of CaCl2 solution and 50.0 mL of 0.070 mol/L of NaOH solution are combined?


Do I need to find the solubility product for CaCl2 and NaOH before I can determine if a precipitate will form when they're added to Ca(OH)2. Any help will be greatful. I don't even know if I'm on the right track or not.

Thanks

 

[chemisttree]

Help please!

Here's the question I'm having problems with:

The solubility product of calcium hydroxide, Ca(OH)2, is 7.9 x 10^-6 at 25 degrees celcius. Will a precipitate form when 100mL of 0.10 mol/L of CaCl2 solution and 50.0 mL of 0.070 mol/L of NaOH solution are combined?


Do I need to find the solubility product for CaCl2 and NaOH before I can determine if a precipitate will form when they're added to Ca(OH)2. Any help will be greatful. I don't even know if I'm on the right track or not.

Thanks

Assume that CaCl2 and NaOH are both soluble at the specified concentrations.

 

[Blueshift5]

Hello,

To determine if a precipitate will form when the two solutions are combined, you will need to calculate the concentrations of Ca2+ and OH- ions in the final solution. This can be done using the concentrations and volumes of the solutions being combined.

First, use the formula C1V1 = C2V2 to calculate the number of moles of Ca2+ and OH- ions in each solution. For CaCl2, you will have (0.10 mol/L)(0.100 L) = 0.010 mol of Ca2+ ions. For NaOH, you will have (0.070 mol/L)(0.050 L) = 0.0035 mol of OH- ions.

Next, use the solubility product constant (Ksp) to determine if a precipitate will form. The Ksp for Ca(OH)2 is 7.9 x 10^-6. The Ksp expression for this reaction is:

Ksp = [Ca2+][OH-]^2

Substituting in the values we calculated earlier, we get:

7.9 x 10^-6 = (0.010 mol/L)(x mol/L)^2

Solving for x, we get [OH-] = 0.028 mol/L.

Since the concentration of OH- ions is greater than the solubility product, a precipitate of Ca(OH)2 will form when the solutions are combined. Therefore, the answer to the original question is yes, a precipitate will form.

I hope this helps and clarifies the steps needed to solve this problem. Let me know if you have any further questions.