Determine whether or not each metal dissolves in 1 M HCl. For those metals that do dissolve, write a balanced redox reaction showing what happens when the metal dissolves. a. Al

Video transcript

hey everyone in this example, we're asked whether chromium metal will dissolve in one molar hydrochloric acid. And if yes, we need to write the bounce redox reaction that occurs upon dissolving this metal. So we should recall that we're going to need to refer to our standard electrode potential table either online or in our textbooks and we're going to go ahead and see that on this table, we would see the reduction of H plus where this is going to gain two electrons because we have two moles of H plus to form H two gas. And on this table this has a value Equal to 0.00V. On the other hand, when we find chromium on this table, we would see that our chromium metal, sorry C. R. S. So our chromium metal here is formed from the chromium three plus catalon gaining three electrons. And on our table this has an electrode value equal to negative 0.73 volts. And we would see that because this negative 0.73 volts from our chromium Is less than 0V, we would say therefore chromium will dissolve In one molar hydrochloric acid. So our next step is to balance out our half reactions here and in order to do so we need to go ahead and make sure that they have the same number of electrons. So we have two electrons in our reduction of our H plus carry on and we have three electrons in our oxidation of chromium. So we want to go ahead and think of a number that can bounce these out and that would be six. So we would go ahead and multiply in brackets are first half reaction by three. And then our second half reaction, we would go ahead and multiply this by two. And so this would give us new values for our electrons so that we now have for our first half reaction, six moles of Rh plus plus now six electrons yields three moles of our H two gas, sorry. And then for our second half reaction, we would have two moles of chromium metal produced from two moles of the chromium three plus cat ion Plus our six electrons here and so adding up these two half reactions, we would get our balanced net redox reaction Which is going to be six moles of Rh plus Plus two moles of chromium metal yields three moles of H two gas Plus two moles of our chromium catalon. And so this here would be our final our second answer here. So our first answer was that chromium will dissolve in the one molar hydrochloric acid because it has a voltage that is less than zero volts from the reduction of H Plus and then our second final answer here is this bounce redox reaction highlighted in yellow. So I hope that everything I reviewed was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video