Question

One step in making para-aminobenzoic acid, PABA, an ingredient in some suntan lotions,
involves replacing one of the hydrogen atoms in a toluene molecule with an - NO2 group,
directly opposite the -CH3 group. Calculate the percent yield if 550 g of toluene added to an
excess of nitric acid provides 305 g of the nitrotoluene product.​

Answer 1

Answer:

The percentage yield of the reaction is 37.24%.

Explanation:

Experimental yield of nitrotoluene product = 305 g

Theoretical yield of nitrotoluene product = ?

Percentage yield:

$\% yield =\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Theoretical yield of nitrotoluene product:

$CH_3-C_6H_5+HNO_3\rightarrow CH_3-C_6H_4-NO_2+H_2O$

Moles of toluene = $\frac{550 g}{92 g/mol}=5.9783 mol$

According to reaction 1 mole of toluene gives 1 mole of nitrotoluene product.

Then 5.9783 moles of toluene will give:

$\frac{1}{1}\times 5.9783 mol=5.9783 mol$ of nitrotoluene.

Mass of 5.9783 moles of nitrotoluene:

5.9783 mol × 137 g/mol = 819.03 g

Percentage yield of the reaction:

$\% yield =\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

$\% yield =\frac{305 g}{819.03 g}\times 100=37.24\%$