Question

I perform a chemical reaction in a test tube and a gas is given off. When I hold a glowing wooden splint over the mouth of the test tube, it relights.
What gas am I?

Answer 1

Answer:

Oxygen gas causes a glowing splint to continue burning. If you observe a gas forming, test for its identity by inserting a glowing wood splint into the mouth of the test tube.

Explanation:

test tube holder wooden test tube rack ... Place the burning splint into the mouth of the test tube without dropping it into the test ... If carbon dioxide gas is present, it will put the flame out.