Which of the following represents a chemical property of hydrogen gas?

• A. It exists as a gas at room temperature.
• B. It is less dense than air.
• C. It reacts explosively with oxygen gas.
• D. It is a colorless gas.
• E. It is a tasteless molecule.

Answer: (C)

Verified step by step guidance

1. Understand the difference between physical and chemical properties. Physical properties are characteristics that can be observed without changing the substance's chemical identity, such as color, density, and state of matter. Chemical properties describe how a substance interacts with other substances, leading to a change in chemical composition.
2. Identify the options given in the problem. The options are: existence as a gas at room temperature, being less dense than air, reacting explosively with oxygen gas, being colorless, and being tasteless.
3. Determine which of these options involves a change in chemical composition. A chemical property involves a substance's ability to undergo a chemical reaction, resulting in new substances.
4. Recognize that the option 'It reacts explosively with oxygen gas' describes a chemical reaction. When hydrogen gas reacts with oxygen, it forms water, which is a different chemical substance, indicating a chemical property.
5. Conclude that the correct answer is the option that involves a chemical change, which is 'It reacts explosively with oxygen gas.' This is a chemical property because it describes hydrogen's ability to undergo a chemical reaction with oxygen.