What is the difference between displacement and double displacement reaction? Give suitable chemical equations for the same. (3 marks)
Answers
Answer:
The reaction in which an atom or a set of atoms are displaced by another atom in a molecule is called displacement reaction. For instance, when Iron is added to a copper sulfate solution, it displaces the copper metal.
A + B – C → A – C + B
The above equation exists when A is more reactive than B.
The reaction in which two atoms or a group of atoms are displaced by another atom in a molecule is called a double displacement reaction.
A-B + C-D → A-C + B-D
A and B have to be either:
Halogens where C indicates a cation.
Different metals wherein C indicates an anion.
The difference between displacement reaction double displacement reaction is tabulated below:
Single Displacement reaction Double displacement reaction
In a displacement reaction, a more reactive element replaces a less reactive element from a compound. In a double displacement reaction, two atoms or a group of atoms switch places to form new compounds.
In a displacement reaction, one displacement takes place.
A + BX → AX + B
In a double displacement reaction, two displacements take place to complete the reaction.
AB + CD → AC + BD
Change in color takes place with no precipitate forms. Precipitate is formed.
Metals react with the salt solution of another metal. Salt solutions of two different metals react with each other.
Examples:
2KI + Cl2 → 2KCl + I2 is a displacement reaction.
CuSO4 + Zn → ZnSO4 + Cu is also a displacement reaction.
Examples:
Na2SO4 + BaCl2 → BaSO4 + 2NaCl is a double displacement reaction.
2KBr + BaCl2 → 2KCl + BaBr2 is also a double displacement reaction.
☛ Those reactions in which one element takes place of another element in a compound are known as displacement reaction.
☛ In general,a more reactive element displace a less reactive element from it's compound.
☛ Example:- when a strip of zinc metal is placed in copper sulphate Solution ,then zinc sulphate Solution and copper are obtained.
☛ Those reactions in which two compounds react by an exchange of ions to form two new compounds are called double displacement reaction.
☛ A double displacement reaction usually occurs in Solution and one of the products,being insoluble out.
☛ Example :- When silver nitrate Solution is added to sodium chloride solution then a white precipitate of silver chloride is formed along with sodium nitrate Solution.