Stoichiometric Calculation Based Question

UF₆→ U + 3F₂  

C + 2F₂→ CF₄  ……….. (2)

From reaction (2),

1 mole CF₄ is prepared from 2 mole F₂

Then, 1.25 mole CF₄  will be prepared from F₂ = (2 mol/1 mol)*(1.25 mol) = 2.5 mol

Hence, from reaction (2) it is clear that 2.5 mole F₂  is required to produce 1.25 mole CF₄

From reaction (1)

3 mole F₂ is produced from 1 mole UF₆

Then, 2.5 mole F₂ will be produce from UF₆ = (1 mol/3 mol)*(2.5 mol) = 0.83 mol   

Hence, 0.83 mole UF₆ would have to be decomposed to provide enough fluorine to prepare 1.25 mole CF₄.