What chemical combination could cause an explosive reaction when used in the same container?

The combination of quicklime and alum can lead to an explosive reaction due to the highly exothermic nature of the reaction between quicklime, which is calcium oxide, and water. When quicklime comes into contact with water, it forms calcium hydroxide and releases a significant amount of heat. Alum, which contains sulfates, can also interact with the products formed, potentially leading to rapid thermal reactions, especially in environments where there's high moisture content.

This vigorous reaction can produce gases that may build up pressure if contained, resulting in an explosive situation. Understanding the properties and potential reactivity of each chemical is crucial in drinking water treatment processes to ensure operational safety and to prevent hazardous conditions.