Final answer:
The splint test confirms the presence of oxygen by observing if a glowing ember on a wooden splint reignites when placed in a gas sample. In pure oxygen, the ember burns brighter due to a higher concentration of oxygen compared to air.
Step-by-step explanation:
The purpose of the splint test is to confirm the presence of oxygen gas (O2). This test relies on the principle that combustion requires oxygen, and by using a glowing splint, we can observe whether a gas sample contains oxygen. The test is conducted as follows: if we have a splint with a glowing ember and insert it into a container with a gaseous sample, the behaviour of the ember will indicate the presence of oxygen. In a gas sample without oxygen, the glowing ember will extinguish. However, in the presence of oxygen, the ember will reignite or burn more brightly, especially if the gas is pure oxygen, due to the increased reaction rate from a higher concentration of the reactant, which is oxygen in this case.
Therefore, A) Confirming the presence of oxygen is the correct answer to the question, as the splint test detects the ability of a gas to support the combustion of a glowing splint, which is unique to oxygen among the common gaseous substances.