One half of an electrochemical cell consists of a pure nickle electrode in a 0.001 molal solution,
and the other half is a cadmium electrode immersed in a 0.5 molal solution. The electrode
potential is given by , where is the standard electrode potential and c is the molal concentration
of the ions in the solution. The cell potential is most likely?
a) -0.65 V
b) -0.15 V
c) -0.073 V
d) +0.75 V
Standard electrode potential for Cd and Ni are
E0Cd2+/Cd = -0.403 V and E0Ni2+/Ni = -0.250 V
Hence Cd2+/Cd will be the anode and Ni2+/Ni will be the cathode
Using Nernst equations
E = E0 + (0.059/2) * log (Cion)
ECd2+/Cd = E0Cd2+/Cd + (0.059/2)log(0.5) =-0.403 + (0.059/2)log(0.5) = -0.4118 V
Similarly,
ENi2+/Ni = E0Ni2+/Ni + (0.059/2)log(0.5) =-0.250 + (0.059/2)log(0.001) = -0.3385 V
Cell potential will be
E = ENi2+/Ni - ECd2+/Cd = -0.3385 – (-0.4118) = + 0.0733 V
note: may be the option " c) -0.073" be replaced by the option " c) +0.073"
Get Answers For Free
Most questions answered within 1 hours.