What is the reduction half-reaction for the following unbalanced redox equation?
Cr2O7^2– + NH4^+ Cr2O3 + N2
A.Cr2O3--> Cr2O7^2–
B.Cr2O7^2– --> Cr2O3
C.NH4^+ --> N2
D.N2 --> NH4^+
I think this is D...?
In a, the Cr in the dichromate ion is 6
in the chromate ion, the Cr is 3, so each Cr must lose three electrons in that reaction. It is an oxidation of the Cr ion.
Look at B CAREFULLY> you need to think these out. Smart girls don't guess.