Answer to Question #156247 in General Chemistry for Mohammad Hossain

Question

In a H2 fuel cell, electricity is produced by oxidation-reduction reaction between H2 and O2 gases. Draw a diagram of H2 – O2 fuel cell and write down the cell reaction of that fuel cell. At STP 89.6 L H2 gas is passed in H2 fuel cell which reacts with O2 for 20 minutes. What is the average strength of electricity (in ampere) produced? If total current produced is passed in CuSO4 solution of electrolytic cell, then what amount of Cu metal will be deposited at cathode?

Answer 1

In a fuel cell

Anode reaction: H₂ + 2OH^- = 2H₂O + 2e^-

Cathode reaction: O₂ + 2H₂O + 2e^- = 4OH^-

Moles of H₂ reacting = 89.6 / 22.4 = 4 moles

Equivalent of H₂ used = 4 x 2 = 8

Now, W / E_w = It / 96500

8 = (I x 20 x 60) / 96500

I = 643.33 A

Also, equivalent of H₂ = equivalent of Cu formed

Equivalent of Cu deposited = 8

W_Cu = 8 x 63.5/2 = 254 g

Thus, weight of Cu deposited = 254 g.