Ok, so there is acid present throughout.
Anyway this is irrelevant for the yield calculation.
You have your reaction equation: 1 mole starting material goes to 1 mole product.
You have the density of butan-1-ol and the amount in mL. Therefore you can work out how many grams this is equivalent to, hence you know how many moles butan-1-ol you used. Consequently you now know the theoretical yield.