Similar topic, I can't seem to get my head around these half-reactions when they get a bit more complicated.
Question: Write cell diagrams* using the following pairs of half-reactions. For half-rections in which all the reactants are in solution, assume the use of inert platinum electrodes. Identify the anode and the cathode.
f)
NO3- (aq) + 4H+ + 3e- <--> NO(g) + 2H2O (l)
MnO4- (aq) + 8H+ (aq) + 5e- <--> Mn2+ + 4H2O (l)
My answer:
anode ---> Pt | NO (g), NO3- || MnO4-, Mn2+ | Pt <-- cathode
Actual answer:
anode ---> Pt | H+ (aq), NO3- || MnO4-, Mn2+, H+ (aq) | Pt <-- cathode
I guess I'm just generally confused... something I'm missing... like where is the NO (g).... what part are the H+ ions playing here....?
*(Do you do cell diagrams in VCE? The are written like: anode | electrocyte at anode || electrolyte at cathode | cathode