Question

Which two reactions are opposites?

synthesis and decomposition
single-displacement and double-displacement

Answer 1

Answer: synthesis and decomposition

Explanation: Synthesis is a chemical reaction in which two or more than two reactants react together to form a single substance.

`2Mg +O_2\rightarrow2MgO`

Decomposition is a chemical reaction in which a single reactant decomposes to give two or more than two products.

`CaCO_3 \rightarrow CaO+CO_2`

Single displacement reaction is the one which a more reactive element displaces a less reactive element from a solution.

`Zn +CuSO_4 \rightarrow ZnSO_4+Cu`

Double displacement reaction is the one which exchange of ions take place.

`ZnCl_2 + CuSO_(4) \rightarrow CuCl_2 + ZnSO_4`