Final answer:
Auto gas, or LPG, is stored in a compressed liquid state but is released and burned as a vapor, which means it is in a gaseous state during combustion. The correct answer to the question is b) Gaseous form.
Step-by-step explanation:
The student's question is asking about the state in which autogas is stored and released when burned. Autogas is often referenced as Liquefied Petroleum Gas (LPG) and is primarily composed of propane and butane. While LPG is stored in a compressed liquid state, it is released as a vapor when it's burned, meaning it is in a gaseous form during combustion. This is similar to gaseous butane being compressed within the storage compartment of a disposable lighter, resulting in its condensation to the liquid state. When the butane is released and burned, it returns to its gaseous form.
Liquefied gases like LPG are stored under increased pressure or at low temperatures to keep them in liquid form. This is practical for transportation and storage because it takes up less space. Upon decreasing the pressure or increasing the temperature, these liquids revert back to their gaseous state. This phenomenon is crucial for the use of these gases as fuels.