What is a skeletal equation exactly?
The question asks:
Consider a reaction in acid solution involving species of manganese and chromium.
Half reaction
MnO2 + 4H+ + 2e- --> Mn2+ + 2H2O
Reduction potential
Eo = +1.23 V
Half reaction
Cr2O72- + 14 H+ + 6e- --> 2Cr3+ + 7H2O
Reduction potential
Eo = +1.33 V
i. write correctly balanced half-reactions and the net ionic equation for the skeletal equations shown
how do i do this accurately? What do I do with the H2O molecules and everything else? I'm confused.
equations are correctly balanced and we just need to add them together to get the final net ionic equation
Now the reaction with high reduction potential is the one which will take place at the cathode and will undergo reductions .
Second equation will undergo oxidation and reaction will take place at the anode.
We need to reverse the oxidation reaction
Cr2O72- + 14 H+ + 6e- --> 2Cr3+ + 7H2O(reduction)(cathode)
3(Mn2+ + 2H2O -->MnO2 + 4H+ + 2e-)
3Mn2+ + 6H2O -->3MnO2 + 12H+ + 6e-(anode)
On adding the above reactions the net ionic reaction is
Cr2O72- + 2 H+ +3Mn2+ --> 2Cr3+ + H2O+3MnO2
Ecell = Ecathode - Eanode
= 1.33-1.23= 0.10 V