Final answer:
The oxidizing agent that supplies oxygen gas to develop color molecules and create a change in natural hair color is hydrogen peroxide.
Step-by-step explanation:
The oxidizing agent that, when mixed with an oxidation haircolor, supplies the oxygen gas to develop the color molecules and create a change in natural hair color is hydrogen peroxide (H₂O₂).
In the process of permanent hair coloring, hydrogen peroxide acts as an oxidant and donates oxygen molecules to the color molecules present in the hair dye. This oxidation reaction leads to the formation of larger dye molecules that are locked inside the hair, resulting in a permanent color change.
It is important to note that hydrogen peroxide is commonly used as a bleaching agent as well, due to its ability to react with colored organic compounds and turn them into colorless ones.