Ethyne undergoes cyclic polymerization to form benzene, which is subsequently nitrated to form nitrobenzene. The percentage yield for the polymerization step is 40 % , and for the nitration step is 50 % . If 39 g of ethyne is used initially, the mass of nitrobenzene formed is x 10⁻¹ g . The value of x is ________. (Given atomic masses in g mol ⁻¹ : C =12 , H =1 , N =14 , O =16 )

Step-by-step solution

Molar mass of ethyne ( C ₂ H ₂ ) = 26 g mol ⁻¹ Initial moles of ethyne = 39 26 = 1.5 mol Step 1: 3 C ₂ H ₂ C ₆ H ₆ Theoretical moles of benzene = 1.5 3 = 0.5 mol Actual moles of benzene produced (with 40 % yield) = 0.5 0.40 = 0.2 mol Step 2: C ₆ H ₆ C ₆ H ₅ NO ₂ Theoretical moles of nitrobenzene = 0.2 mol Actual moles of nitrobenzene produced (with 50 % yield) = 0.2 0.50 = 0.1 mol Molar mass of nitrobenzene ( C ₆ H ₅ NO ₂ ) = 123 g mol ⁻¹ Mass of nitrobenzene formed = 0.1 123 = 12.3 g = 123 10⁻¹ g Thus, the value o