Which of the following reaction is not oxidation-reduction reaction?

Oxidation-reduction reaction, also called redox reaction, any chemical reaction in which the oxidation number of a participating chemical species changes. The term covers a large and diverse body of processes. Many oxidation-reduction reactions are as common and familiar as fire, the rusting and dissolution of metals, the browning of fruit, and respiration and photosynthesis - basic life functions.

​ Key Points

• Most oxidation-reduction (redox) processes involve the transfer of oxygen atoms, hydrogen atoms, or electrons, with all three processes sharing two important characteristics:

1. They have coupled i.e.in any oxidation reaction a reciprocal reduction occurs.
2. They involve a characteristic net chemical change i.e., an atom or electron goes from one unit of matter to another. 

• CH4 + 2O2 → CO2 + 2H2O in this reaction transfer of hydrogen takes place.
• Fe2O3 + 3C → 2Fe + 3CO in this reaction transfer of oxygen takes place.
• 3CuO + 2NH3 → 3Cu + N2 + 3H2O in this reaction transfer of oxygen and hydrogen both takes place.

Hence, we can conclude that Ca(OH)2 + 2CH3COOH → Ca(CH3COO)2 + 2H2O this is not oxidation-reduction reaction.

Additional Information

• Ca(OH)2 + 2CH3COOH → Ca(CH3COO)2 + 2H2O this is example of neutralization reaction.
• The reaction of an acid with a base is called a neutralization reaction 
• It results in the formation of salt. Also, the H+ ion of acid and OH- ion of base combine to form water.