* Activity Series: Magnesium is more reactive than aluminum. This means that magnesium would displace aluminum from its compound if a reaction were to occur. However, aluminum is already in its most stable ionic form (Al³⁺) in aluminum sulfate.

* No Driving Force: For a reaction to happen, there needs to be a driving force like the formation of a gas, precipitate, or a significant change in energy. In this case, there is no clear driving force for a reaction.

* Stability: Aluminum sulfate is a relatively stable compound, and magnesium is not strong enough to displace aluminum from it.

Therefore, magnesium and aluminum sulfate will not react under normal conditions.