Predict the anode, cathode, and overall cell reactions when an aqueous solution of each of the following salts is electrolyzed in a cell having inert electrodes. (b) CuCl₂

Video transcript

Hello. In this problem, we were asked what are the cathode a node And overall cell reactions for the electrolysis in a cell with inert electrodes of the aqueous solution of chromium to iodized salt. So let's begin by considering those reactions that could take place at the cathode. Recall that reduction occurs at the cathode. We have an aqueous solution. So that means that we could have water being reduced form hydrogen gas and hydroxide ions. Standard reduction potential is equal to negative 0.83V. We could also have our chromium two ions being reduced to form chromium metal. The standard reduction potential Is equal to negative 0.91V. When we consider these standard reduction potentials, the one that is less negative is going to indicate than which of these has the greater potential to be reduced. So in this case than water has a greater potential to be reduced to form hydrogen. So this is the reaction then that will occur at the cathode. If you consider what reactions could occur at the anodes, recall that oxidation takes place at the anodes. So again, we have water. The water could now be oxidized form oxygen gas and how do nines. The standard oxidation potential is equal to negative 1.23V. And we could also have then our I died be oxidized to form iodine And this has a standard oxidation potential of -0.54V. When comparing the standard oxidation potentials the one that is less negative then will indicate which half reaction will occur. The anodes. So that means that I died has a greater potential than to be oxidized. So this will be our reaction taking place at the anodes. Now to find the overall cell reaction, we're going to combine the reaction taking place at the cathode with that one taking place at the and we want to make sure that the number of electrons that are being gained is equal to the number of electrons that are being lost in this case they are. So we'll combine those things that appear on the reactant side are, electrons will cancel and then we'll combine things that appear on the product side. So our overall reaction then we have two moles of water Reacting with two moles by died going to form hi Dine And hydrogen gas and two moles of hydroxide ions. So this will then be our overall cell reaction. This then all corresponds to answer C. Thanks for watching. Hope this helps