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How long will it take for a uniform current of 6.00 A to deposit 78 g of gold from a solution of A u C l 4 - ? What mass of chlorine gas will be formed simultaneously at anode of the cell? (Atomic mass of Au = 197)

Options

  1. At = 3010 sec, w = 35.50 g
  2. Bt = 20306 sec, w = 45.54 g
  3. Ct = 19500 sec, w = 54.5 g
  4. Dt = 19139.16 sec, w = 42.24 g

Correct answer

D. t = 19139.16 sec, w = 42.24 g

Step-by-step solution

Reactions take place at electrodes are At cathode A u C l 4 - + 3 e - → A u + 4 C l - At cathode C l - → 1 2 C l 2 + e - For the deposition of 197 g (1 mole) of Au = 3F of charge is required thus, for the deposition of 78 g of Au, charge required = 3 197 × 78 = 1.19 F = 1.19 × 96500 coulumbs From Q = I × t t = Q I = 1.19 × 96500 6 = 19139.16 sec By 1 F charge, 35.5 g of C l 2 gas is formed, thus from 1.19 F, mass of chlorine gas formed = 35.5 × 1.19 = 42.24 g

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