Moles of Bromine produced = 9 moles
Further explanation
Given
9 moles of Chlorine gas
Word equation
Required
Moles of Chlorine produced
Solution
We change the word equation into a chemical equation (with a formula)
Aluminum bromide reacts with chlorine gas to produce Aluminum chloride and bromide gas
2AlBr₃+3Cl₂⇒2AlCl₃+3Br₂
moles Cl₂ = 9
Maybe you mean, how many moles of Bromine can we produce?
From equation, mol ratio Cl₂ : Br₂ = 3 : 3, so mol Br₂=mol Cl₂=9 moles