Spontaneous combustion can occur when chlorine is mixed with which substance?

Spontaneous combustion can occur when chlorine is mixed with activated carbon due to the highly reactive nature of chlorine gas. When chlorine interacts with activated carbon, it can result in an exothermic reaction that generates heat. If there is sufficient heat build-up within the mixture and the conditions are right, this can lead to spontaneous ignition. Activated carbon serves as a source of combustible material, and in the presence of chlorine, it can ignite without the need for an external ignition source.

In contrast, while aluminum, iron oxide, and sodium bicarbonate can also react with chlorine, the nature of those reactions does not typically lead to spontaneous combustion. For example, aluminum may react with chlorine to form aluminum chloride, but this does not result in an exothermic reaction that could spontaneously ignite. Iron oxide and sodium bicarbonate have similar considerations, where their reactions with chlorine don't create the explosive risk associated with activated carbon.