Which one of the following is not an oxidation reaction?

Oxidation is a chemical process involving the gain of oxygen or the loss of electrons [3]. Rusting of iron is a classic oxidation reaction where iron reacts with oxygen and moisture to form hydrated iron(III) oxide [1]. Rancidity occurs when fats and oils in food undergo oxidation, leading to spoilage [3]. Combustion is a rapid oxidation-reduction (redox) reaction where a substance reacts with oxygen to release energy [3]. In contrast, opening a soda bottle is a physical process rather than a chemical oxidation reaction. It involves the release of dissolved carbon dioxide gas (degassing) due to a decrease in pressure [4]. This process does not involve the transfer of electrons or the formation of new chemical oxides, making it the only non-oxidation process among the given options.

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > CuO +H Cu+H O 2 2 → Heat (1.29) > p. 12
2. [3] Science-Class VII . NCERT(Revised ed 2025) > Chapter 5: Changes Around Us: Physical and Chemical > 5.3.1 Rusting > p. 62
3. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Oxidation and Reduction > p. 91
4. [4] https://www.sciencedirect.com/science/article/abs/pii/B9780128195239000147