Answer
$Al(CH_{3}COO)_{3}$
Work Step by Step
An ionic compound will always have a neutral charge. The problem states that an Aluminium (Al) ion will have a charge of +3 while Acetate ($(CH_{3}COO)$) has a charge of -1. Hence, to make the overall charge neutral, there must be three Acetates for one Aluminium ion, making the chemical formula for this compound $Al(CH_{3}COO)_{3}$.
