Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> What is the difference between displacement and double displacement reactions? Write relevant equations for the above.

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> A displacement reaction is the one when a more reactive substance displaces a less reactive one from its salt solution whereas a double displacement reaction is the one where a mutual exchange of ions happens between two compounds.
In a displacement reaction, only a single displacement takes place whereas in the double displacement reaction, as the name suggests two displacement takes place between the molecules.

Example:
Displacement reaction: $Mg\left(s\right)+2HCl\left(aq\right)\to MgC{l}_2\left(aq\right)+H_2\left(g\right)$
Double displacement reaction:
$2KBr\left(aq\right)+Ba{I}_2\left(aq\right)\to 2KI\left(aq\right)+BaB{r}_2\left(s\right)$