IGCSE Chemistry Practice Exam 2025 – Complete Study Resource

Chlorine at room temperature is characterized as a greenish-yellow gas. This distinctive green hue comes from chlorine's molecular structure and how it interacts with light. As a diatomic molecule (Cl2), chlorine is a non-metal element that exists in a gaseous state under normal atmospheric conditions.

While the choice indicating ‘green gas’ captures the essence of chlorine's appearance, it is important to note that the alternative answers misrepresent chlorine’s actual state and color. A clear gas would suggest a colorless and potentially harmless substance, which does not accurately reflect chlorine’s hazardous nature. Similarly, identifying chlorine as a yellow liquid or a brown solid would be incorrect as it does not exist in those states or colors at room temperature.

Therefore, the recognition of chlorine as a green gas aligns with both its physical properties and its behavior under typical conditions.