Question

An iron fence is left unpainted, and it reacts with the oxygen in the air, forming rust. The formation of rust is an oxidation-reduction reaction, but it is also an example of a _________ reaction

Answer 1

I'm pretty sure it would be a chemical reaction.

Answer 2

Answer: This reaction is a type of synthesis reaction.

Explanation: When iron reacts with oxygen which is available in air, it leads to the formation of a reddish-brown compound known as rust.

This reaction is considered as oxidation-reduction reaction because iron is getting oxidized to $Fe^{2+}$ and oxygen is getting reduced to oxide ion.

Equation of the rust follows:

$4Fe(s)+3O_2(g)+nH_2O(l)\rightarrow 2Fe_2O_3.nH_2O$

Synthesis reactions are defined as the reactions in which two or more than two reactants combine together to form a single product which can be a molecule or a compound.

The rusting of iron is also considered as a synthesis reaction because iron and oxygen are combining together to form a single compound known as rust.

Both these reactions are a type of Chemical reactions.