Question

Which of the following is a type of double decomposition reaction?
(A)- Neutralization reaction
(B)- Precipitation Reaction
(C)- Electrolytic decomposition
(D)- All of the above

Answer 1

Hint: In the double displacement reaction, consisting of two compounds in such a manner that the ions in the reactants get displaced from its original position and form a new bond with another ion of the reactant. Thus, two new compounds are formed in the reaction.

Complete step by step answer:
As can be seen, in the electrolytic decomposition of the compound into its constituent elements on passing current through its aqueous solution.
For example, in the reaction of electrolysis of molten sodium chloride which breaks into sodium metal at the cathode and the chlorine gas at the anode.
$2Na(l)\to 2Na(s)+C{{l}_{2}}(g)$
Then, in case of neutralization reaction, where the acid and base react forming an ionic salt and water. During this process, it is seen that the reactant ions producing ${{H}^{+}}\,and\,O{{H}^{-}}$ ions respectively combines and form water along with the salt. Hence, displacement can be seen. For example:
\[\begin{align}
  & \text{Acid: }HCl\to {{H}^{+}}+C{{l}^{-}} \\
 & \text{Base: }NaOH\to N{{a}^{+}}+O{{H}^{-}} \\
 & \text{then,}\,HCl(aq)+NaOH(aq)\to NaCl(aq)+{{H}_{2}}O(l) \\
\end{align}\]
Also, in the precipitation reaction between two aqueous ionic compounds, forming an insoluble precipitate at the end. As the ions in the aqueous solution displace one another, such that the cations and anions in both the molecules exchange places forming two entirely different molecules. For example: in the reaction between barium chloride and sodium sulphate in aqueous solution form a barium sulphate (precipitate) and sodium chloride through displacement of reactant ions.
$BaC{{l}_{2}}\,(aq)+N{{a}_{2}}S{{O}_{4}}\,(aq)\to BaS{{O}_{4}}\,(s)+2NaCl\,(aq)$

Therefore, option (A)- Neutralization reaction and option (B) precipitation reaction, both are types of double displacement reaction.

Note: The double displacement is also known as the double replacement reaction, due to the ions getting replaced in the two reactants among each other.
The electrolytic decomposition also known as the electrolysis process due to the current being passed through the solution is the opposite of the combination reaction.