Exercise 4 | Electrochemistry

Given that [Al3+] = 1.00 x 10-2 M, what is the reduction potential for the following half-reaction:

Al3+ (aq) + 3 e- → Al (s)?


Data: E0red [Al3+] = - 1.66 V at 25°C 

Nernst equation:
 

At 25°C:
 

Ered = E0redRTνeF x ln Q = E0red0.02570νe x ln Q


Ered = reduction potential (in V)
E0red = -1.66V
νe = stoichiometric coefficient of the electrons = 3
Q = reaction quotient = 1 / [Al3+]

 

Ered = E0red0.02570νe x ln Q

Ered = - 1.66 + 0.025703 x ln 0.200

Ered = - 1.70 V