Question

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...?

Answer 1

in D, nitrogen atoms lose electrons, that is oxidation, right?

Answer 2

right

Answer 3

So D is not reduction.

Answer 4

A is a reduction

Answer 5

bob for some reason these questions are throwing me off - I need to understand this

Answer 6

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.

Answer 7

Cassie: figure the oxidation state in each ion, on each side, then figure out what change occured: losing or gaining electrons.

Answer 8

http://www.shodor.org/unchem/advanced/redox/index.html

Answer 9

I know and I don't want to guess - I want to know it...automatically

Answer 10

thank you for your help

Answer 11

this didnt help