Question

Determine the theoretical and percent yield of hydrogen gas if 80.5 g water undergoes electrolysis to produce hydrogen and oxygen and 2.81 g hydrogen is collected.
theoretical yield

Answer 1

% yield = (exp.yield)/(theoretical) x 100%

exp. yield = 2.81g

to find theoretical yield;

1. Construct a balance equation for water electrolysed into H2 and O2. Note the mole ratio between H2O and H2.

2. calculate the mole of H2O using n = m/Mr where m is 80.5g and Mr is molar mass of water.

3. Use the mole in 2 to find the mole of H2 using the mole ratio from the balance equation in 1.

4. Use the mole in 3 to find the mass of H2 using m = nMr where n is the mole in 3 and Mr is the molar mass of H2.

the mass you find will be your theoretical yield.

plug in your values and calculate for % yield.


hope that helps..