Question

What is an oxidation reaction? Give an example of oxidation reaction. Is oxidation an exothermic or an endothermic reaction?

Answer 1

Hint:Chemical reactions are the reactant which undergoes a chemical change and product which are formed during a chemical change. There are several types of reactions namely decomposition reaction, combination reactions, oxidation and reduction reactions, displacement reaction, etc.

Complete step by step answer:
Oxidation increases the oxidation state of element, removal of hydrogen or gain of oxygen corresponds to oxidation reaction.
Oxidation reactions are those reactions in which oxidation of a compound or a molecule takes place. The compound which oxidizes other compounds is known as an oxidizing agent like nitric acid. During oxidation, substances lose hydrogen or gain oxygen during a reaction. The oxidation leads to increase in oxidation state of the oxidized substance and decrease in oxidation state of oxidizing agent because during oxidation, oxidizing agent oxidizes others at the cost of reduction themselves. Example of oxidation reaction is oxidation of copper by oxygen results in formation of copper oxide. The reaction is as follow as:
 \[2{\text{C}}{{\text{u}}_{\left( {\text{s}} \right)}} + {{\text{O}}_2}_{\left( {\text{g}} \right)}\xrightarrow{{{\text{heat}}}}2{\text{CuO}}\] ,
This causes the surface of copper powder to turn black due to coating of copper oxide on the surface of copper because of oxidation by oxygen gas. As we can see, oxidation states of copper change from zero to \[ + 2\] , increase in oxidation state during oxidation and on the other hand, oxidation state of oxygen changes from zero to \[ - 2\] , decrease in oxidation state. Also, heat is required to oxidize the copper. Thereby, oxidation reactions are endothermic reactions.
Reduction reaction involves decrease in oxidation state of element with removal of oxygen or addition of hydrogen by the reducing agent. In a redox reaction, one reactant gets oxidized and the other gets reduced simultaneously during a reaction.

Note:
Oxidation state of an atom is the charge present on the atom when it is in combined state with another element. We can simply say the oxidation state of an element in a compound represents the number of electrons lost or gained during its change from Free State into that compound.