(b) Write the half-reaction that occurs at a hydrogen electrode in acidic aqueous solution when it serves as the anode of a voltaic cell.

Video transcript

Welcome back everyone. What is the half reaction taking place at the electrode when a hydrogen electrode acts as the anodes in an acidic aqueous solution. So we want to recall that for our an ode of our voltaic cell, this occurs as an oxidation and we know that this occurs as an oxidation because our oxidation number will increase. And so if we have the oxidation of our hydrogen to hydride as a cat ion, we would form the following reaction where we have hydrogen gas, which forms hydride, where we should have two moles of hydride and to cancel out that net plus two charge from the coefficient of two, we're going to gain two electrons or release rather two electrons on the product side. And because electrons are on the product side, we recognize this as an oxidation. So for our final answer, we have this entire half reaction here. I hope everything I explained was clear and I'll see everyone in the next practice video.