Solution

A redox reaction is one in which oxidation and reduction take place simultaneously. In $BaCl_2 + Na_2SO_4 \rightarrow BaSO_4 + 2NaCl$, the oxidation numbers of all elements are the same in the reactants and products, so no oxidation or reduction takes place. So this is NOT a redox reaction (it is a double displacement/precipitation reaction).

Concept Distinguishing metathesis from redox reactions

Redox Reactions in past papers

30 questions from this chapter have appeared across 19 exam years.