Final answer:
If the splint does not continue to burn or glow when inserted into a gas, it indicates the presence of carbon dioxide.
Step-by-step explanation:
If a sample of the dry salt is treated with a small amount of acid, the production of carbon dioxide is a positive test for a carbonate. For example, the chemical test used to identify a gas as oxygen, or not, relies on the fact that increasing the concentration of a reactant increases reaction rate. If we insert a glowing splint into any gas that does not contain oxygen, the splint will immediately cease to glow. Therefore, if a splint test is performed and the splint does not continue to burn or glow when inserted into a gas, it indicates the presence of carbon dioxide.