Can Fe2+ be separated from Sn2+ by bubbling H2S through a 0.3 M HCl solution that contains 0.01 M Fe2+ and 0.01 M Sn2+? A saturated solution of H2S has [H2S] ≈ 0.10 M. Values of Kspa are 6 x 10^2 for FeS andd 1 x 10^-5 for SnS.

Video transcript

Hello everyone today. We have the following problem. A 0.25 molar nitric acid solution contains 0.20 molar of zinc two plus and 20.0 to molar of nickel two plus can bubbling hydrogen sulfide through the solution, separate zinc from nickel. The hydrogen sulfide and a saturated solution of hydrogen sulfide is approximately 0.10 moller. And then we have the following K. S. P. A. Values. So from his question, it stated that this hydrogen sulfide can in fact react with these two to form the solid zinc sulfide and solid zinc or nickel sulfide. So we have to do is we have to use this liability product in the acid R. K. S. P. A. So how is that going to look? We're going to name this, our M as for our solid reacting with our acid, this is going to form our metal two plus ions as well as our hydrogen sulfide ions. And of course water balancing this out, we're just gonna add a two in front of the water and a two in front of the hydro knee. Um And so now we're going to have to use our K. S. P. A. Values. That is going to be our products overreacting. So we're going to have our M. Two plus times are hydrogen sulfide divided by our hydro ni. Um and our hydro name is going to have a two as an exponent because of the coefficient, has it too. We're not gonna include the M. S. Because that is a solid and solid and are included in this. And I used em to just generalize the fact that it could be zinc or it could be nickel, it will get more specific in later in this problem. So now we have the following K. Sp A expression. So essentially a precipitate will form if our Q quotient is greater than our K. S. P. A. Value. And so let's factor in for our zinc sulfide first. So our zinc sulfide is going to react with two of our hydro knee um ions. And this is gonna give us zinc two plus ions as well as our hydrogen sulfide. And lastly our two water our K. S. P. A expression is going to be our zinc two plus, followed by our hydrogen sulfide. And then lastly our Hydro knee um with you two is the exponent and essentially it's gonna be the same for our nickel sulfide. It's gonna react with the same reactant This time however, it's going to yield Nickel two plus and then the hydrogen sulfide and then our two waters in the liquid form. We're then going to calculate or write out our K. Sp expression once again Which is essentially going to be our Nickel two plus times our hydrogen sulfide divided by our hydro me. Um With the two is the exponent. Next we have to calculate that proton concentration we have to and in order to do that, we're going to take the concentration of hydro nia. We're going to equal that too. We're gonna have our polarity for our acid. Our polarity was 0.25 moles per one liter. And we're gonna multiply by the multiple ratio of nitric acid, two protons or hydrogen protons. That's going to be for every one mole of our nitric acid. We only have one hydrogen in that formula. So I'm just gonna say that we have one hydrogen. Our units are gonna cancel out. We're going to get 0.25 molar for our concentration of hydro ni. Um So now we can plug this in to our que equations are K. S. P A. R. Queue equations for each of these solids and find if it will precipitate or not. So we're going to have our zinc sulfide. Our cue is going to be equal to our 0.02. This is using the equation earlier over 0.25 squared. Which will give us 0.032. And then for our nickel sulfide we have Q. Is equal to R 0.2 times 0.1 divided by 0.25 squared. This will also give us 0.32. So if you look at both of our Q values, our Q values are actually less than both of our K. S. P values. So what can we conclude from this? We can conclude that there will be no precipitation. However, we can also conclude that bubbling our hydrogen sulfide can indeed separate zinc two plus from nickel to plus, and this is due two zinc sulfide precipitating first because it has that greater K. S. P. And so this is going to be our final answer. Overall, I do hope this helped, and until next time.