Determine the theoretical and percent yield of hydrogen gas if 78.5 g water undergoes electrolysis to produce hydrogen and oxygen and 3.23 g hydrogen is collected.

Answer 1

theoretical yield can be determined using the equation for electrolysis of water and the mass

2H2O --> 2H2 + O2
mole of water is 78.5g/18gmol-1 = 4.36
mole ratio of H2O:H2 is 2:2 i.e. same moles. mole of H2 is 4.36x2 = 8.72moles

Theoretical mass or yield of Hydrogen is nMr = 8.72moles x 1 = 8.72g.

experimental yield is given as 3.23g

percentage yield is
(experimental/theoretical)X 100%

hope that helps

Answer 2

correction: theoretical mass is 8.72moles x 2 = 17.44g