Based on Faraday's 1st law of electrolysis, total electric current passed in AlCl3 = I = Q X T where Q = electric charge, T = time (in seconds) Given, Q = 15 A, T = 3.5 h = 3.5 X 60 X 60 s = 12600 s ∴ I = 15 X 12600 = 189000 C
Now, based on Faraday's 2nd law of electrolysis we have, W = ZIT where, W= weight of electrolyte deposited/evolved at any electrode Z= electrochemical equivalent T= time (s) I = electric current in present case, Electrochemical Equivalent of Al = [tex] \frac{26.98}{3} [/tex] = 8.993 g and I = 189000 C ∴ W = 8.993 X 189000 X 12600 = 2.141X [tex] 10^{10} [/tex] g