Answer
A synthesis reaction is a chemical reaction in which multiple reactants combine to form a single product while a decomposition reaction is the separation of a single chemical compound into two or more elements.
Example of a synthesis reaction is: $2Na + Cl_{2} --> 2NaCl$
Example of a decomposition reaction is: $2Al_{2}O_{3} --> 4Al + 3O_{2}$
Work Step by Step
A synthesis reaction is a chemical reaction in which multiple reactants combine to form a single product while a decomposition reaction is the separation of a single chemical compound into two or more elements.
Example of a synthesis reaction is: $2Na + Cl_{2} --> 2NaCl$
Example of a decomposition reaction is: $2Al_{2}O_{3} --> 4Al + 3O_{2}$