Which apparatus would you use to collect oxygen gas from potassium chlorate?

To collect oxygen gas produced from the thermal decomposition of potassium chlorate (KClO3), you would use an upside-down test tube or gas jar, set up in a fume hood or well-ventilated area. The reaction is typically facilitated by heating KClO3 in the presence of a catalyst like manganese dioxide (MnO2). The oxygen gas generated can be collected over water, but for dry oxygen, direct collection in an inverted container is preferred.