Answer
See explanation below.
Work Step by Step
The reaction is:
3 Cd2+(aq) + 2 Cr(s) --> 3 Cd(s) + 2 Cr3+(aq)
E cell = -0.40 V - (-0.74 V)
= 0.34 V
In order to reverse the reaction, 0.34 V is required ,with the cell in its standard state. A 1.5 V supplies more potential, and hence the cadmium metal oxidizes to Cd2+ and chromium plates out.
