Which is an example of a double replacement reaction?
2Na+ Cl2 + 2NaCl
H2SO3 → H20 + S02
2K + 2H20 – 2KOH + H2
NaCl + AgF-NaF + AgCI

NaCl + AgF → NaF + AgCl

Explanation:

A double replacement reaction is a type of chemical reaction that occurs when two reactants exchange cations or anions to yield two new products.

From all the reactions given ,

2Na + Cl₂ → 2NaCl is an example of combination reaction because two or more reactants (Na & Cl₂) react with each other to form a single product (NaCl)H₂SO₃ → H₂O + SO₂ is an example of decomposition reaction because a single reactant (H₂SO₃) breaks down into two or more products (H₂O & SO₂).2K + 2H₂O → 2KOH + H₂ is an example of displacement reaction because a highly reactive element (K) displaces a least reactive element (H) from its compound (H₂O).NaCl + AgF → NaF + AgCl is an example of double replacement reaction because there's an exchange between Cations ( & ) and Anions ( & ).

How do we find the answer?

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab.