Question

A voltaic cell is constructed from a standard Cr3+Cr half cell (E® red = -0.740V) and a standard Cu2+ Cut half cell (E® red = 0.153V). (Use the lowest possible coefficients. Use the pull-down boxes to specify states such as (aq) or (s). If a box is not needed, leave it blank.) The anode reaction is: DB + + The cathode reaction is: The spontaneous cell reaction is: + 1 D- ODO The cell voltage is v.

Answer 1

1)

a)

Oxidation takes place on Anode.

The one with smaller Eo value will be oxidised.

So, the anode reaction is:

Cr(s) —> Cr3+(aq) + 3 e-

b)

Reduction takes place on Cathode.

The one with greater Eo value will be reduced.

So, the Cathode reaction is:

Cu2+(aq) + e- —> Cu+(aq)

C)

Overall reaction is:

3 Cu2+(aq) + Cr(s) -> 3 Cu+(aq) + Cr3+(aq)

d)

Eo cell = Eo cathode - Eo anode

= 0.153 V - (-0.740 V)

= 0.893 V

Answer: 0.893 V