How many moles of bromine are needed to produce 5 moles of aluminum bromide

7.5 mol

Step-by-step explanation:

2Al + 3Br₂ ⟶ 2AlBr₃

You want to convert moles of AlBr₃ to moles of Br₂.

The molar ratio is 3 mol Br₂:2 mol AlBr₃.

Moles of Br₂ = 5 * 3/2

Moles of Br₂ = 7.5 mol Br₂

You need 7.5 mol of Br₂ to produce 5 mol of AlBr₃.