Question

What is the difference between displacement over double displacement reactions ?

• A. Single elements replace double elements
• B. Double elements replaces single elements
• C. Heat is evolved
• D. Heat is not evolved

Answer 1

The correct option is A Single elements replace double elements

In a displacement reaction, a more reactive element replaces a less reactive element from a compound.
$A+BX\to AX+B$; where A is more reactive than B
In a double displacement reactions, two atoms or a group of atoms shift places to form new compounds.
$AB+CD\to AD+CB$
Displacement reaction :
$CuS{O}_4\left(aq\right)+Zn\left(s\right)\to ZnS{O}_4\left(aq\right)+Cu\left(s\right)$
Double displacement reaction :
$N{a}_{2}S{O}_4\left(aq\right)+BaC{l}_2\left(aq\right)\to BaS{O}_4\left(s\right)+2NaCl\left(aq\right)$