Question

3. Consider a Ni2+ solution. How much NI deposits on the cathode if a current of 0.150A is applied for 12.2 minutes?

4. Consider an electrochemical cell based on the following reaction:

Zn(s) + 2H2O(l) + 2OH-(aq) ⇄ [Zn(OH)4]2-(aq) + H2(g)

All dissolved species are at 2.5 x 10-3 M; pressure of H2 is 1 bar (standard state) Use the Nernst equation to calculate E.

Answer 1

3)

time = 12.2 min = 12.2 x 60 sec

       = 732 seconds

current = i = 0.150 A

equivalence weight = E = 29.345

F = faraday = 96485 C

weight deposited = E x i x t / F

                           = 29.345 x 0.150 x 732 / 96485

                          = 0.0334 g

weight of Ni deposited = 0.0334 g