Consider the Fischer ester synthesis of methyl benzoate from benzoic acid and methanol in the presence of sulfuric acid as a catalyst. A reaction was performed in which 3.6 g of benzoic acid was reacted with excess methanol to make 1.4 g of methyl benzoate. Calculate the theoretical yield and percent yield for this reaction.

The percent yield of the reaction is 32.04 %.

Explanation:

To calculate the number of moles, we use the equation:

    .....(1)

Given mass of benzoic acid = 3.6 g

Molar mass of benzoic acid = 112.12 g/mol

Putting values in equation 1, we get:

The chemical equation for the formation of methyl benzoate from benzoic acid follows:

By Stoichiometry of the reaction:

1 mole of benzoic acid produces 1 mole of methyl benzoate

So, 0.0321 moles of benzoic acid will produce = of methyl benzoate

Now, calculating the mass of methyl benzoate from equation 1, we get:

Molar mass of methyl benzoate = 136.15 g/mol

Moles of methyl benzoate = 0.0321 moles

Putting values in equation 1, we get:

To calculate the percentage yield of methyl benzoate, we use the equation:

Experimental yield of methyl benzoate = 1.4 g

Theoretical yield of methyl benzoate = 4.37 g

Putting values in above equation, we get:

Hence, the percent yield of the reaction is 32.04 %.