Question

What are the products of a double displacement reaction?

Answer 1

Double displacement reaction is defined as the reaction in which solutions of two compounds react with each other to form two new compounds. This type of reaction is based on the reactivity series of metals which we will see in the solution. In this reaction, the anions of two solutions or compounds get exchanged and hence, two new chemical compounds are formed.

Complete answer:
We know that in the double displacement reactions, the reactants are two chemical compounds (or solutions) and the cations or anions get exchanged between them. This type of reaction is based on the reactivity series of metals which is given as follows:
$K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$
Now, we will see a double displacement reaction between Potassium Iodide with Lead Nitrate solution as follows:
$2{\text{ }}KI(aq) + \;\;Pb{(N{O_3})_2}(aq)\; \to Pb{I_2}\left( s \right)\; + \;2{\text{ }}KN{O_3}\left( {aq} \right)$
From the above mentioned reactivity series, we can see that Potassium is the most reactive metal and hence, it will displace Lead (Pb) from Lead Nitrate solution. Hence, Potassium nitrate is formed. After that, Lead ions react with the iodide ions to form Lead iodide solution.
Therefore, in double displacement reactions, the products formed are two new chemical compounds. One of the compounds formed is a precipitate and hence, we can say that one compound is an insoluble ionic compound.

Note:
We should note that there are many more types of chemical reactions which are as follows: Combination reactions, decomposition reactions, displacement reactions, double displacement reactions and redox reactions. In redox reactions oxidation and reduction reactions take place simultaneously.