Question

I need to find the theoretical yield of benzoic acid from this lab experiment. The first part of the experiment involved this formula

C6H5COOH + NaOH ------> C6H5COO-Na+ + H2O where we mixed 30 mL of a stock solution of toluene-benzoic acid mixture and then added 15.0 mL of aqueous sodium hydroxide to seperate the two layers.

In the second part, C6H5COO-Na + Hcl-------> C6H5COOH + NaCl we took the aqueous layer extracted from the mixture in the first part and added 70 mL of 10% aqueous hydrochloric acid to acidify it.

A week later once it was dried, we obtained .5002 grams of benzoic acid.

Please show the work of how you found the theoretical yield.

Answer 1

and 1 g of Toluene should give = (1*122.12) / 92.14 = 1.33 g of benzoic acid. This is theoretical yield.

and % yield = (Actual yield) / theoretical yield * 100 %

In our case Actual yield = 0.5002 g.

% yield = (0.5002) / 1.33 * 100 % = 37.61 % yield.

If you have measured the toluene amount in mL then you can use formula for conversion of mass in to volume using its density.

Density of Toluene = mass / volume

mass of Toluene = Volume * Density (0.867 g/mL)