1. The problem statement, all variables and given/known data Toluene (C6H5CH3) is hydrogenated according to the two simultaneous chemical reactions C6H5CH3 + H2 → C6H6 + CH4 2C6H5CH3 + H2 → (C6H5)2 + 2CH4 Initially, the reactor contains 40% toluene and 60% H2 (% mole). At the end of the operation, the reactor contains 10% toluene and 30% CH4 (% mole). Find: a. The mole fraction of the diphenyl, (C6H5)2, at the end of the operation b. The conversion of H2 2. Relevant equations I came up with the following equations from the molar balances(a,b and c are the final mole fractions of H2, Benzene and Biphenyl, respectively, ε1 and ε2 are the extents of reactions): 0.1=(0.4*n1-ε1-2*ε2)/n2 a=(0.6*n1-ε1-ε2)/n2 b=ε1/n2 0.3=(ε1+2*ε2)/n2 c=ε2/n2 3. The attempt at a solution The final amount of moles n2 is related to the initial amount by the following equation: n2=n1=0.4*n1-ε1-2*ε2+0.6*n1-ε1-ε2+ε1+ε1+2*ε2+ε2 Now I have five equations with six unknowns but I can suppose an initial amount of moles of 10 and then solve the equations with five unknowns. However this system of equations is unsolvable. I'm studying stoichiometry and found this problem inside a reactor design book. Any help would be welcome. Thanks.