"Self-ignition" experiment

How to make a mixture of potassium permanganate and sulfuric acid ignite?

Chemists are real ma­gi­cians, be­cause they can ig­nite sub­stances with­out match­es or fire. This fas­ci­nat­ing ex­per­i­ment demon­strates how potas­si­um per­man­ganate self-ig­nites from the im­pact of sul­fu­ric acid.

Reagents and equip­ment:

  • 10 g of potas­si­um per­man­ganate;
  • 1 ml of con­cen­trat­ed sul­fu­ric acid;
  • porce­lain tile.

Step-by-step in­struc­tions

For the ex­per­i­ment, we take sev­er­al grams of potas­si­um per­man­ganate and sprin­kle it on a ce­ram­ic tile. Care­ful­ly pour a small amount of con­cen­trat­ed sul­fu­ric acid on it. The drops be­come green – this is the col­or of per­man­gan­ic an­hy­dride [man­ganese ox­ide (VII)]. Sev­er­al sec­onds lat­er the “vol­cano” bursts into flames and emits smoke.

Pro­cess­es de­scrip­tion

Potas­si­um per­man­ganate is a strong ox­i­diz­er. When potas­si­um per­man­ganate comes into con­tact with the drops of con­cen­trat­ed sul­fu­ric acid, the un­sta­ble man­ganese ox­ide Mn₂O₇ is formed, which col­ors the drops of sul­fu­ric acid green. Short­ly af­ter­wards the “vol­cano erupts”: a bright flash with the re­lease of brown “vol­canic smoke”. This takes place as a re­sult of the break­down of the un­sta­ble ox­ide (VII) Mn₂O₇ to man­ganese ox­ide (IV) MnO₂ and oxy­gen O₂.

Safe­ty pre­cau­tions

When work­ing with con­cen­trat­ed sul­fu­ric acid, wear rub­ber gloves and pro­tec­tive glass­es, as it will cause burns if it comes into con­tact with your eyes or skin.

Warn­ing! Sub­stances of this ex­per­i­ment are tox­ic and high­ly dan­ger­ous for your health. Do not try this at home. Only un­der pro­fes­sion­al su­per­vi­sion.

Try it