Question

Given the following organic equation and data, calculate the experimental percent yield of benzoic acid in grams:

11.29 mL of ethyl benzoate was reacted with 6.3 grams of sodium hydroxide under reflux conditions using ethylene glycol and water as the solvents. After workup, 6.67 grams of benzoic acid was recovered.

you will have to determine limiting reagent, calculate theoretical yield and finally, calculate the percent yield.

Give answer in this format: XX.X %

Answer 1

C2H5OOCC6H5 + NaOH----------------> C6H5COOH + H2O

In this ethyl benzoate was given ml first we have to convert ml in to gram

That we have to use the following equation

Density = mass /volume

Mass (g)= density / volume

Density of ethyl benzoate is 1.05 g/ml

Volume of ethyl benzoate is 11.29ml

Therefore mass = 1.05 g/ml x 11.29 ml

                              = 11.85 g

Then we have know the molar mass reactant

molar mass of ethyl benzoate =150.17g/mol molar mass of NaOH = 40 g/mol then we have to calculate moles of the reactant moles of ethyl benzoate = mass/molar mass                                   = 11.85g/(150.17g/mol)                                   = 0.0789mol moles of NaOH = mass/molar mass                                          = 6.3g/(40g/mol)                                          = 0.1575 mol From the balanced chemical equation we know that for every mole of ethyl benzoate and NaOH one mole of benzoic acid is produced. Since there are more moles of NaOH than ethyl benzoate , ethyl benzoate is used up first as the reaction proceeds. We can conclude that NaOH is in excess and ethyl benzoate is the limiting. Since ethyl benzoate is the limiting reagent. Therefore moles of ethyl benzoate = moles of the product( benzoic acid produced moles of ethyl benzoate which is equal to moles of benzoic acid = 0.0789 mole. Finding the Theoretical Yield Theoretical Yield = moles of benzoic acid x molar mass of benzoic acid ( 122.12 g/mole)                          = 0.0789 mol x 122.12g/mol                          = 9.6352 g Finding the Percent Yield Percent Yield =         Actual Yield        x 100%                             Theoretical Yield                     =    6.67g      x 100 %                           9.6352g                     = 69.2 %