In a double-replacement reaction, there are two reactants and product(s

Two

Explanation:

In a double-replacement reaction, there will be two reactants and two products.

It is called double replacement reaction because one element in reactant 1 replaces an element in reactant 2 and other element in reactant 2 replaces other element in reactant 1.

Here two replacements are taking place. Hence, this is called double replacement reaction.

A Neutralization reaction i.e an Acid - Base reaction is a good example of Double replacement reaction.

An Example is provided below for better understanding :

HNO3 + NaOH --> NaNO₃ + H₂O.

Here HNO₃ is the acid and NaOH is the base which are the reactants.

NaNO₃ and H₂O are the products.

This is a double replacement reaction because,

Hydrogen(H) in  HNO₃ replaces Sodium(Na) in NaOH, and

NO₃ in HNO₃ replaces OH in NaOH.

Here, there are 2 reactants and 2 products.

increased stability in the completion of fluorine's outer shell.