Question

Give an example of a reaction in which precipitate is formed.

Answer 1

In the given question, we are required to find an example of a chemical reaction in which precipitate is formed. We should know the different kinds of chemical reactions. We also must know the definition of precipitation to solve the given problem.

Complete answer:
Precipitation reactions are reactions occurring in an aqueous solution medium in which two ionic bonds combine resulting in the formation of insoluble salt. These insoluble salts formed in the reaction are called precipitates.
There are many such reactions involving the formation of precipitate. One of the most common and simple reactions is the reaction between the aqueous solutions of potassium chloride and silver nitrate. The reaction is as follows:
$AgNO_3 (aq) + KCl (aq) \to AgCl (ppt) + KNO_3 (aq)$
Potassium nitrate and silver chloride are the products of the given chemical reaction. Silver chloride is precipitated out in the reaction. Hence, the overall reaction is known as precipitation reaction and the product, silver chloride formed in the reaction is known as precipitation. The precipitate of sodium chloride is of white color and is insoluble in water or aqueous solutions.
Precipitation reactions help us to determine the constituent reactants and conditions of chemical reactions. They are also known as ionic reactions as ions react actively in the formation of precipitate.

Note:
We must denote the physical state of each reactant and product in the reaction by writing $\left( s \right)$ for solid, $\left( {aq} \right)$ for aqueous solution, $\left( {ppt} \right)$ for precipitate. Precipitation reactions are mostly double displacement reactions in which a solid chemical substance is left as a residue.