Question

A voltaic cell is constructed with a compartment of Aluminum strip in a solution of Al(NO₃)₃ and a standard hydrogen Electrode.

A) which is the cathode?

B) Write the two half reactions.

C) Will the aluminum strip gain or lose mass?

D) Write a balanced equation for the overall cell reaction.

E) What is the cell potential if the concentration of  Al(NO₃)₃ is 0.200 M?

Hello! I completed steps a-d and i really just had a question about "E", does the concentration have effect on the cell potential, should I be using NERNST equation for this?

Answer 1

E)

yes concentration of Al(NO₃)₃ will effect the cell potential .

Eocell = Eocathode - Eo anode

           = 0.00 - (-1.66 )

          = 1.66 V

overall cell reaction :    2 Al (s) + 3 H2 ---------------------> 2 Al³⁺(aq) + 6 H+ (aq)

Q = [Al3+]^2 [H+]^6 / PH2

for SHE , H+ = 1.00 M , pH2 = 1.00 atm

Q = (0.200)^2

Q = 0.04

Ecell = Eocell - 0.05916 / n * log Q

        = 1.66 - 0.05916 / 6 * log (0.04)

       = 1.67 V

Ecell = 1.67 V