Question

Which of the following equations is not an example of a single displacement reaction?
(A) \[2Al+F{{e}_{2}}{{O}_{3}}\to A{{l}_{2}}{{O}_{3}}+2Fe\]
(B) \[Ca+C{{l}_{2}}\to CaC{{l}_{2}}\]
(C) \[2KI+C{{l}_{2}}\to 2KCl+{{I}_{2}}\]
(D) \[2Na+2{{H}_{2}}O\to 2NaOH+{{H}_{2}}\]

Answer 1

Hint: Displacement reaction is a type of reaction in which part of one reactant is replaced by another reactant. It is of two types: Single displacement reaction and double displacement reaction.

Complete step by step solution:
Displacement reaction is the reaction in which reactant of one part is replaced by the reactant of another part. There are two types of displacement reactions:
Single displacement reaction: In this type of reaction one reactant replaces the part of the other.
\[XY+Z\to XZ+Y\]
Double displacement reaction: It is the reaction where the cations and anions in the reactant interchange with each other to form products.
\[AB+CD\to AD+CB\]
\[2Al+F{{e}_{2}}{{O}_{3}}\to A{{l}_{2}}{{O}_{3}}+2Fe\]: It is a displacement reaction in which Fe is replaced by Al and \[F{{e}_{2}}{{O}_{3}}\] is changed in to\[A{{l}_{2}}{{O}_{3}}\].
\[Ca+C{{l}_{2}}\to CaC{{l}_{2}}\]: This type of reactions are known as composition reactions in which two substances combine to make a single substance.
 \[2KI+C{{l}_{2}}\to 2KCl+{{I}_{2}}\]: This is also a displacement reaction in which I (Iodine) is replaced with Cl (Chlorine).
\[2Na+2{{H}_{2}}O\to 2NaOH+{{H}_{2}}\]: We can also consider this reaction as a single displacement reaction in which one reactant is combined with another one like OH molecule is attached with Na (Sodium).

Thus, the correct answer is (B).

Note: (A),(C) and (D) are single displacement type reactions in which one reactant replaces the path of another. Reaction c is a composition type reaction. Displacement reactions can also be known by two other names called replacement reaction or metathesis reaction.