What test can be used to confirm the presence of hydrogen gas?

The presence of hydrogen gas can be confirmed by the characteristic "pop" sound that it makes when ignited with a lit splint. When hydrogen is mixed with oxygen and exposed to a flame, it burns very quickly and produces a distinct popping sound, which is a key identifying feature of hydrogen. This reaction occurs because hydrogen is a highly flammable gas, and when sufficiently mixed with oxygen and ignited, it undergoes combustion.

In contrast, testing with a glowing splint may indicate the presence of oxygen if the splint relights; however, it does not specifically test for hydrogen. Using litmus paper is associated with testing for acids or bases, but it does not provide any information about hydrogen gas. Additionally, measuring temperature change with a thermometer would not confirm the presence of hydrogen gas; the temperature change is not a direct indicator of hydrogen's presence or behavior in a reaction. Thus, the method involving the use of a lit splint is the reliable test for identifying hydrogen gas.