During rainy season power supply to our home from the electric pole will be interrupted due to formation of metallic oxide layer on the electric wire. This is ________ type of reaction.

The power supply is taking place from electric pole to home by moving free electrons from Aluminum (Al). But in a rainy season, formation of metallic oxide takes place on the electric wire. This is due to passive $\text{A}{l}_2{\text{O}}_3$ film is formed and it can act as good insulator to electricity passing.