Question

Oxygen ______combustion and is ____itself.

Answer 1

Before answering this question, we should have an idea of what is a combustible and non-combustible substance. When a substance can burn in air and produce heat and light is known as a combustible substance. Such substances are called non-combustible substances. Combustible substances can only burn if there are necessary ingredients such as heat, fuel and air.

Complete answer:
Oxygen supports combustion and is non-combustible itself.
Oxygen is not flammable, but it is an oxidizer. Oxygen needs fire, so it is dangerous to use around something that is burning, because it will help the fire to burn more quickly. Therefore, we can say that oxygen is a non-combustible gas.
Oxygen supports the chemical processes that occur during fire. When fuel burns, it reacts with oxygen from the surrounding air, releasing heat and generating combustion products. This process is known as oxidation.
When a fire burns, a process called oxidation occurs, the same process that causes metal to rust. Oxidation is when oxygen atoms combine with carbon and hydrogen to form carbon dioxide and water. When metal rusts, the process happens very slowly, but when a fire burns, heat and energy is released very quickly.

Note:
Remember there is a difference between is combustion and supports combustion any gas that supports combustion is a combustion supporter gas on the other hand a gas is combustible in itself is a self-combustible gas. Any combustion reaction mandatorily requires Oxygen for supporting but oxygen does not burn or explode when exposed to ignition source alone.