Magnesium metal is produced by the electrolysis of molten magnesium chloride using inert electrodes. (a) Sketch the cell, label the anode and cathode, indicate the sign of the electrodes, and show the direction of electron and ion flow.

Video transcript

Hello. In this problem, we are asked to draw the cell, set it for the electrolysis of molten zinc chloride and indicate the direction of the flow of electrons. Let's begin by writing the reactions that take place at each electrode. So at the cathode we will have zinc ions being reduced form zinc metal. The standard reduction potential is equal to get 1.662V. And the reaction that's taking place at the node will be the oxidation of Floridians form flooring gas. And the standard oxidation potential is equal to negative of the standard reduction potential. This is equal to negative 1.358V. So we can combine these two reactions to then get the overall reaction. So we see then that we have two electrons being gained and two electrons being lost. So those will cancel. So overall reaction then we have zinc ions reacting with forged irons form zinc metal and boring gas. And the standard cell potential is equal to the standard reduction potential plus the standard oxidation potential. And this works out then -3.02V. Given that the standard cell potential is negative. This is an electrolytic cell where the electrolysis is taking place. Since it's a non spontaneous reaction, we need to be connected to a battery as shown here. So when we look at these two cell setups, we know that the zinc metal then is going to be reduced at the cathode. So we should have the zinc metal associated with the cathode which is not in this case. And we should have then the chloride ions that are being oxidized at the an ode, and that's not the case in the cells shown above. And since this is an electrolytic cell, that a node is the positive electrode, the cathode is the negative electrode and the electrons are going to move from the anodes to the cathode. So the cell setup shown in B then is the correct setup. Thanks for watching Hope. This help.