With which substance should sulfuric acid not be stored?

Sulfuric acid should not be stored with potassium permanganate due to the highly reactive nature of both substances. When sulfuric acid comes into contact with potassium permanganate, a strong oxidizer, it can lead to a vigorous exothermic reaction. This reaction can release heat and produce harmful gases, potentially resulting in an explosive situation if not properly controlled. Because of this potentially dangerous interaction, keeping sulfuric acid separated from potassium permanganate is crucial for safety in any laboratory or storage setting.

In contrast, sodium hydroxide, calcium carbonate, and sodium chloride do not present the same risks when stored with sulfuric acid. Sodium hydroxide can react with sulfuric acid to produce heat and neutralize the acid, but that reaction is typically safe if handled correctly. Calcium carbonate can react with sulfuric acid to produce carbon dioxide and calcium sulfate, which is not hazardous as long as the reaction is managed properly. Sodium chloride is stable and does not pose a significant risk when in proximity to sulfuric acid, making it a safer option for storage.