Question

Calculate the theoretical yield, actual yield, and percent yield. In the experiemnt conducted 1.04 grams of p-nitrobenzoic acid was added to 30 mL of diethyl ether and then transferred in a seprartory funnel. 15 mL of 5% NaOH was added and the layers were separated. This was done twice to separate the organic from the aqueous layer then vaccum filtration was used to get the salt. I got .12g of salt but I am confused as to how you find the theoretical yield, actual yield, and percent yield from just this information. Please write steps on how you calculate.

Answer 1

The reaction of diethyl ether with p-nitrobenzoic acid (molar mass 167) will give p-nitrobenzaldehyde. As this reaction will not be 100% so there will be unreacted p-nitrobenzoic acid. This unreacted p-nitrobenzoic acid will react with NaOH to give p-nitro sodium benzoate ( molar mass: 189 g/mol)

the mass of p-nitrobenzoic acid initially = 1.04 g

So, the moles of p-nitrobenzoic acid initially = 1.04/167 = 0.006227 moles

So, the moles of p-nitro sodium benzoate that should have been obtained = 0.006227 moles

So, the theoretical yield the mass of p-nitro sodium benzoate that should have been obtained = 0.006227 * 189 = 1.1769 g

The actual yield = 0.12 g

So percentage yield = (0.12/1.1769 )*100 % = 10.196 %