The preparation of 2,4-dichloronitrobenzene from nitrobenzene and chlorine gas is an electrophilic aromatic substitution reaction. The balanced chemical equation for this reaction is:C6H5NO2 + 2 Cl2 C6H3Cl2NO2 + 2 HClTo calculate the theoretical yield, we need to find the molar mass of nitrobenzene and 2,4-dichloronitrobenzene and then use stoichiometry.Molar mass of nitrobenzene C6H5NO2 = 6 12.01 + 5 1.01 + 1 14.01 + 2 16.00 = 123.11 g/molMolar mass of 2,4-dichloronitrobenzene C6H3Cl2NO2 = 6 12.01 + 3 1.01 + 2 35.45 + 1 14.01 + 2 16.00 = 180.99 g/molNow, we can use stoichiometry to find the theoretical yield:10 g nitrobenzene 1 mol nitrobenzene / 123.11 g nitrobenzene 1 mol 2,4-dichloronitrobenzene / 1 mol nitrobenzene 180.99 g 2,4-dichloronitrobenzene / 1 mol 2,4-dichloronitrobenzene = 14.71 g 2,4-dichloronitrobenzeneThe theoretical yield of the reaction is 14.71 g of 2,4-dichloronitrobenzene.