Certified Pulmonary Function Technologist (CPFT) Practice Exam

The Geissler tube ionizer is specifically designed to analyze gases that are capable of being ionized and measured for their physical and chemical properties. Helium is commonly used in Geissler tubes because of its inert nature and low molecular weight, making it an ideal candidate for analysis.

When an electric field is applied to the Geissler tube containing helium gas, it ionizes the gas and produces a measurable discharge, which can then be analyzed. Helium's unique characteristics allow for clear readings and reliable results in various applications, particularly in scientific and educational settings.

While oxygen, nitrogen, and carbon dioxide are important gases in various contexts, they do not have the same level of application in a Geissler tube due to factors such as reactivity, molecular properties, and the specific detection methods favored for those gases. Thus, helium stands out as the correct gas associated with a Geissler tube ionizer.