To calculate the yield of 2,4-dichlorobenzoic acid, we first need to determine the limiting reactant in the reaction between benzoic acid and chlorine gas. We can do this by comparing the moles of each reactant.The molecular weight of benzoic acid C7H6O2 is: 12.01 x 7 + 1.01 x 6 + 16.00 x 2 = 122.12 g/molThe molecular weight of chlorine gas Cl2 is: 35.45 x 2 = 70.90 g/molNow, we can calculate the moles of each reactant:moles of benzoic acid = 100 g / 122.12 g/mol = 0.819 molesmoles of chlorine gas = 50 g / 70.90 g/mol = 0.705 molesThe balanced chemical equation for the reaction is:C7H6O2 + 2 Cl2 C7H4Cl2O2From the balanced equation, we can see that 1 mole of benzoic acid reacts with 2 moles of chlorine gas. To determine the limiting reactant, we can compare the mole ratio of benzoic acid to chlorine gas:0.819 moles benzoic acid / 1 = 0.8190.705 moles chlorine gas / 2 = 0.3525Since 0.3525 is smaller than 0.819, chlorine gas is the limiting reactant.Now, we can calculate the theoretical yield of 2,4-dichlorobenzoic acid based on the moles of the limiting reactant:moles of 2,4-dichlorobenzoic acid = 0.705 moles Cl2 * 1 mol C7H4Cl2O2 / 2 mol Cl2 = 0.3525 molesThe molecular weight of 2,4-dichlorobenzoic acid C7H4Cl2O2 is: 12.01 x 7 + 1.01 x 4 + 35.45 x 2 + 16.00 x 2 = 197.02 g/molThe theoretical yield of 2,4-dichlorobenzoic acid is:0.3525 moles * 197.02 g/mol = 69.42 gConsidering an 80% yield for the reaction, the actual yield of 2,4-dichlorobenzoic acid would be:69.42 g * 0.80 = 55.54 gTherefore, the yield of 2,4-dichlorobenzoic acid that can be obtained from the reaction is approximately 55.54 grams.