Answer:
[tex]\boxed{ \text{21 mol}}[/tex]
Explanation:
(a) Balanced equation
You haven't given the complete reaction, but we can use a partial equation so long as Cl is balanced.
3Cl₂ + … ⟶ 2FeCl₃ + …
(b). Calculation
You want to convert moles of FeCl₃ to moles of Cl₂
The molar ratio is 3 mol Cl₂:2 mol FeCl₃
[tex]\text{Moles of Cl$_{2}$} =\text{14 mol FeCl$_{3}$} \times \dfrac{\text{3 mol Cl$_{2}$}}{\text{2 mol FeCl$_{3}$}} = \text{21 mol Cl$_{2}$}\\\\\text{You need }\boxed{ \textbf{21 mol of Cl$_{2}$}}\text{ to form 14 mol of FeCl$_{3}$}.[/tex]
