if an aqueous solution of BA(NO3)2 is added to 1.0 L of a solution containing 0.05 mol F- and 0.075 mol SO4 2-, which salt will precipitate first?
Look up Ksp. Calculate (Ba^+2) needed to ppt BaSO4 and BaF2. The one requiring the smallest (Ba^+2) will ppt first.
I have the Ksp.
BaSO4 is 1.1 x 10^-10 and BaF2 is 1.8 x 10^-7
but what do you mean calculate (Ba^2+) needed to ppt BaSO4 and BaF2? how do you do that? that's the part i don't understand.
I misspoke. I thought the sulfate and fluoride were given but they are not. So you need to calculate the solubility
BaSO4 ==> Ba^+2 + SO4^-2
Ksp = (Ba^+)(SO4^-2) = 1.1 x 10^-10.
If we let Ba^+2 = S, then SO4^-2 = S and
S^2 = 1.1 x 10^-10. Solve for S = 1.05 x 10^-5 M which is Ba^+ in a saturated solution of BaSO4.
Do the same thing for BaF2 and calculate Ba^+2. Compare.
Well, it sounds like these ions are really trying to get together and form a solid relationship, I mean a solid precipitate! Let's see which couple is going to tie the knot first.
If we take a look at the solubility rules, we know that most nitrates (NO3-) are soluble. So, BA(NO3)2 would stay dissolved in water and would not precipitate.
Now, let's dive into fluorides (F-) and sulfates (SO4 2-). According to the rules, most fluorides are soluble, except when they're paired up with certain elements like BA. This means that BAF2 could form a beautiful precipitate.
On the other hand, sulfates are usually insoluble, except when they hang out with certain elements like BA (again!). This means that BASO4 could also get cozy and form a solid precipitate.
Now, the million-dollar question: which one will precipitate first? Well, BASO4 is generally less soluble than BAF2, so it's the one that will form a precipitate first. Guess sulfates just couldn't wait to tie the knot!
Hope that clears things up and brings a little chemistry comedy to your day!
To determine which salt will precipitate first when an aqueous solution of BA(NO3)2 is added to a solution containing F- and SO4 2-, we need to consider the solubility rules and determine which salt has the lowest solubility product constant (Ksp).
1. Write the balanced chemical equation for the reaction:
BA(NO3)2 (aq) + 2 F- (aq) ⟶ BAF2 (s) + 2 NO3- (aq)
BA(NO3)2 (aq) + SO4 2- (aq) ⟶ BASO4 (s) + 2 NO3- (aq)
2. Calculate the concentration of each ion after mixing the solutions:
The initial concentration of F- is 0.05 mol/L.
The initial concentration of SO4 2- is 0.075 mol/L.
3. Determine the solubility product constant (Ksp) values:
The Ksp for BAF2 is 1.0 x 10^-6.
The Ksp for BASO4 is 1.0 x 10^-10.
4. Calculate the ion product (IP) for each salt:
For BAF2: IP = [BA2+][F-]^2
For BASO4: IP = [BA2+][SO4 2-]
5. Compare the ion product (IP) with the solubility product constant (Ksp):
- If IP > Ksp, then the salt is supersaturated and will precipitate.
- If IP = Ksp, then the salt is saturated and may or may not precipitate.
- If IP < Ksp, then the salt is unsaturated and will remain in solution.
6. Compare the IP values:
For BAF2: IP = [BA2+][F-]^2
For BASO4: IP = [BA2+][SO4 2-]
Since the IP value for BAF2 is higher than that of BASO4, BAF2 will precipitate first.
So, in this case, BAF2 will precipitate first when an aqueous solution of BA(NO3)2 is added.