Question

Two different electrolytic cells filled with molten $Cu(NO_3)_2$ and molten $Al(N0_3)_3$ respectively are connected in series. When electricity is passed 2. 7 g Al is deposited on electrode. Calculate the weight of Cu deposited on cathode. $[Cu = 63 .5; Al= 27 .0 g mol^{-1} ]$

• A. 190.5 g
• B. 9.525g
• C. 63.5 g
• D. 31.75 g

Answer 1

Answer: (B)

9.525g

Answer 2

According to Faraday II law
$\, \, \, \, \, \frac{w_1}{E_1} = \frac{w_2}{E_2}$ (1 for Al and 2 for copper)
$\frac{2.7 \times 3}{27} = \frac{w_2 \times 2}{63.5} (E_{Al} =27/3, \, and \, E_{cu} =63.5/2)$
$\, \, \, \, \, \, \, \, \, \, w_2 = 9.525g$