Test for oxygen gas using a glowing splint. The gas is produced by the decomposition of hydrogen peroxide, catalysed by solid manganese (IV) oxide. Hydrogen peroxide (H2O2) is unstable, and naturally decomposes very slowly at room temperature, producing water and oxygen gas. The speed of this decomposition can be greatly increased by a catalyst, however. The vigorous reaction produces large quantities of a gas, which bubbles off. When a glowing splint is introduced to the gas, it relights and burns brightly, indicating that it is oxygen.