Which statement is true for the given reaction? Na2SO4 (aq) + Mg (s) →

Magnesium replaces sodium during the reaction.

No reaction occurs.

Magnesium combines with sodium sulfate.

Magnesium replaces sulfate ion during the reaction.

Metals higher in the reactivity series may displace least reactive metals from their salts. For example sodium is reactive than copper therefore it would displace copper ions from its salt. In this case, Sodium is more reactive than Magnesium and therefore magnesium cannot displace sodium ions from sodium sulfate, therefore, no reaction will take place.