Concept:In a double displacement reaction, the ions of two reactants exchange places to form new compounds.
Explanation:In this reaction, two ionic compounds react in aqueous solution and their ions swap partners.
The general equation is
AB+CD→AD+CB.
For example,
AgNO3​+NaCl→AgCl+NaNO3​.
Here,
Ag+ and
Na+ exchange their ions to form a precipitate of
AgCl.
These reactions are also called metathesis reactions.
They are usually identified by the formation of a precipitate, a gas, or water.
The other options are incorrect:
A decomposition reaction breaks a single compound into simpler substances:
AB→A+B.
An addition reaction combines two or more reactants into a single product.
A disproportionation reaction is a redox reaction where one substance is simultaneously oxidised and reduced.
Answer:Option C: Double displacement reaction.