Question

A student designs an ammeter (a device that measures electrical current) that is based on the electrolysis of water into hydrogen and oxygen gases. When electrical current of unknown magnitude is run through the device for 1.50 min , 15.4 mL of water-saturated H2(g) is collected. The temperature and pressure of the system are 25 ∘C and 715 torr.

Calculate the magnitude of the current in amperes if the number of moles of hydrogen gas produced is 5.73×10⁻⁴ mol

Answer 1

From the data,

moles of H2 collected = 5.73 x 10^-4 mol

mole electron used = 5.73 x 10^-4 x 2 = 1.146 x 10^-3 mol e-

coulombs of charge used = 1.146 x 10^-3 x 96500

                                         = 110.59 C

magnitude of current = 110.59/1.50 x 60

                                  = 1.23 Amp