Question

What type of reaction leads to the formation of a precipitate?

Answer 1

Hint: When two ionic compounds react with each other then there is an exchange of cations and anions of the reactants forming two products, if one of the products is insoluble in the solution and the other is the solution, then the first product will form the precipitate in the solution.

Complete answer:
The precipitate is the insoluble product obtained in the reaction. When two ionic compounds react with each other then there is an exchange of cations and anions of the reactants forming two products, if one of the products is insoluble in the solution and the other is the solution, then the first product will form the precipitate in the solution. So, the formation of precipitate in the reaction or precipitation reaction is generally known as a double displacement reaction.
We can study this with an example:
Let us take an example of potassium chloride and silver nitrate; both the compounds are salts because both have a cation and an anion. When these react with each other then, there is the formation of silver chloride and potassium nitrate. The silver chloride is an insoluble salt but the potassium nitrate is a soluble salt, so in the solution silver nitrate will form the white precipitate and the potassium nitrate will be dissolved in the reaction. The reaction is given below:
$AgN{{O}_{3}}+KCl\to AgCl\downarrow +KN{{O}_{3}}$

Note:
With the help of precipitation reaction, we can find the specific cations in the solution, and also it is useful for the extraction of magnesium from the seawater. Not all the double displacement reactions are precipitation reactions.