From the calcuation, the concentration of the copper II ion is 0.98 M.
An electrochemical cell is one in which current is produced by means of a chemical reaction. In this cell, the cell reaction is;
Cd(s) + Cu^2+(aq) ----> Cd^2+(aq) + Cu(s)
E°cell = 0.34 V - (-0.40V) = 0.74 V
Using the Nernst equation;
0.775= 0.74 - 0.0592/2 log(6.5 × 10-2)/[Cu^2+]
0.775 - 0.74 = - 0.0592/2 log(6.5 × 10-2)/[Cu^2+]
0.035 = -0.0296 log(6.5 × 10-2)/[Cu^2+]
0.035 /-0.0296 = log(6.5 × 10-2)/[Cu^2+]
-1.18 = log(6.5 × 10-2)/[Cu^2+]
Antilog (-1.18) = (6.5 × 10-2)/[Cu^2+]
0.066= (6.5 × 10-2)/[Cu^2+]
[Cu^2+] = (6.5 × 10-2)/0.066
[Cu^2+] =0.98 M
Learn more about Nernst equation: https://brainly.com/question/22724431