Question

How many coulombs are required to produce 0.840 L of O2 at 1 atm and 25oC from aqueous H2SO4 solution? use the unbalanced half reaction H2O → O2 (1F = 96485 C/mol).

Answer 1

the balanced equation :

2 H2O (l)   --------------> O2 (g) + 4 H+ (aq) + 4 e-

pressure = 1 atm

volume = 0.840 L

temperature = 25 oC = 298 K

P V = n R T

1 x 0.840 = n x 0.0821 x 298

n = 0.0343

moles of O2 = 0.0343 mol

1 mol O2 ----------> 4 faraday

0.0343 mol ----------> ??

number of faradays = 0.0343 x 4 = 0.137 F

1 F = 96485 C

0.137 F = 0.137 x 96485

               = 13250.7 C

number of coulombs required = 13251 C