Question

Write one difference between displacement and double displacement reaction.

Answer 1

Hint: Try to recall that in displacement reaction a more reactive element displaces a less reactive element whereas in double displacement reactions, cations and anions get exchanged.

Complete step by step solution:

Displacement reaction	Double displacement reaction
When a reactive element displaces a less reactive one from a molecule and takes its place, it is called displacement reaction.	When an interchange of two atoms from two different compounds takes place and the product contains totally different compounds, it is a double displacement reaction.
A general reaction formula is as below: \[AB+C\to AC+B\] Here as you can see, the atom “B” was displaced by atom “C”	A general reaction formula is as below: \[AB+CD\to AC+BD\] The compounds in the product are different from that of reactants because a simultaneous exchange of atoms has taken place.
Example:\[Zn+2HCl\to ZnC{{l}_{2}}+{{H}_{2}}\]	Example: \[MgC{{l}_{2}}+2KOH\to Mg{{(OH)}_{2}}+2KCl\]

Additional information:
- These displacement or double displacement reactions are generally redox reactions, where there is simultaneous oxidation and reduction.
- Oxidation is loss of electrons while reduction is gain of electrons from an atom, molecule or any other charged species.
- The tendency to oxidize or reduce is totally natural to the entity.

Note: These reactions only happen because entities like ions, atoms and molecules always have different relative tendencies of oxidizing or reducing when they are put against one another. In the displacement reaction given above, zinc had a higher tendency to oxidize while hydrogen had a tendency to reduce. And this fact drove the chemical reaction, where both the elements reached a state where they were more stable than their previous forms.