Answer: The percent yield of the reaction is 75 %
Step-by-step explanation:
We are given:
Moles of HgO decomposed = 4.00 moles
The given chemical reaction follows:

By Stoichiometry of the reaction:
2 moles of HgO produces 1 moles of oxygen gas
So, 4.00 moles of HgO will produce =
of oxygen gas
To calculate the percentage yield of the reaction, we use the equation:

Experimental yield of oxygen gas = 1.50 moles
Theoretical yield of oxygen gas = 2.00 moles
Putting values in above equation, we get:

Hence, the percent yield of the reaction is 75 %