Final answer:
1,2-dichloroethane does not readily occur at room temperature because it is a liquid with specific boiling and melting points.
Step-by-step explanation:
1,2-dichloroethane, also known as ethylene dichloride, does not readily occur at room temperature because it is a liquid. It has a boiling point of 83.48°C (182.3°F) and a melting point of -35.7°C (-32.3°F). Therefore, it requires specific conditions, such as heating, to convert it from a solid to a liquid or a gas.