Write a balanced net ionic equation for each of the follow-ing dissolution reactions, and use the appropriate Ksp and Kf values in Appendix C to calculate the equilibrium constant for each. (a) AgI in aqueous NaCN to form [Ag(CN)2]-

Video transcript

Welcome back everyone. What is the net ionic equation for the dissolution of copper to hydroxide and ammonia are solid ability product constant K. S. P. For copper to hydroxide is 1.60 times 10 to the negative 19th power were also given our freezing point depression for copper for ammonia carry on as 5.60 times 10 to the 11th power. We're determining the equilibrium constant for this dissolution reaction. What we're solving for is for the value of K, which is our equilibrium constant. Our first step is to write out the equilibrium that are copper to hydroxide under ghosts. And so this is not one of our memorized strong bases, so it's a weak base and so it does not fully dissociate. So we have this solid which is an equilibrium with its ions as our copper two plus catalon and two moles of hydroxide an ion. Now from the prompt we have the ability product constant for copper to hydroxide which is equal to 1.60 times 10 to the -19 power. But this is also interpreted as the concentration of our products over reactant and we only consider our acquis re agents. So we would just consider this as equal to the concentration of copper caddy on times the concentration of hydroxide in which we have a coefficient of two. So this would be raised to a power of two. Next on the prompt were given are freezing point depression for or sorry, our formation constant K. F for our complex of copper for ammonia catalon. And so we need to show how this complex is formed specifically. We can understand that we have one mole of copper cat ions which react with formals of ammonia. And this is an equilibrium with our complex as copper for ammonia. So N C U NH three sub four. And then we have our two plus caddy in charge. Now make note of the fact that our solvent dissolving our solid copper to hydroxide is R NH three or ammonia, which is the result of our dissolution. And so we're going to now need to make note of the K. F. Formation constant for our complex ion, which is the results of our concentration of our products. So the concentration of our complex copper for ammonia, which is Arkady on And sorry, this should be a bracket divided by our concentration of our reactant is where we have copper two plus catalon And our NH three Ammonia, which has a coefficient of four, which we raise as a power of four here. Now we're going to add up these two equations that we've written out as equilibrium, We're going to add them together and recognize that we can cancel out our one mole of copper cat ions for our second reaction with the one mole of copper catamarans on. The product side from our first reaction and everything else that were left over will make up our overall equation. So we should come up with the following equation where we have one mole of copper to hydroxide. This solid is added to our formals of ammonia and we have this in equilibrium with our one mole of two moles of hydroxide plus our complex being our copper for ammonia cat ion. And because we came up with this overall net ionic equation to find our value for the equilibrium constant. K. Recall that we would say that K is equal to the product between our formation constant and our ability product constant K. S. P. And so K. F times K S. P means we would have our KF given in the prompt as 1.60 times to the negative 19th power, Which is multiplied by RKSP given in the prompt as 5. times 10 to the negative or to the positive 11th power. And so we can say that our equilibrium constant K is equal to a value of 8.96 times 10 to the negative eighth power. So this would be our final answer for the equilibrium constant value as well as our net ionic equation here highlighted in yellow which will correspond to choice a in the multiple choice. I hope that everything I reviewed was clear. If you have any questions, please leave them down below and I'll see everyone in the next practice video