5 posts • Page 1 of 1
The reactions in the question are reversible because they are theoretical. But they're asking you to apply those equations in a galvanic cell, and reactions in galvanic cells go to completion. In a different type of question though, you might have to flip one of the reactions so that one is an oxidizing agent and one is a reducing agent. So that might be why they're written as reversible reactions.
To determine which half reaction is the cathode and anode you have to look at the standard reduction potential. For Co2+ reaction the standard reduction potential is -0.28V and for the Ce4+ reaction the standard reduction potential is +1.61V. Since Ce4+ reaction has a more positive higher voltage it undergoes reduction and is therefore in the cathode which is why it gains electrons in the reaction. You want an overall positive Ecell because it is the reaction in a galvanic cell, spontaneous reaction occurs only with a positive Ecell.
Who is online
Users browsing this forum: No registered users and 2 guests