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

• A. Hydrogen gas is less dense than air.
• B. Hydrogen gas reacts explosively with oxygen to form water.
• C. Hydrogen gas has a density of 0.0899 g/L at STP.
• D. Hydrogen gas is colorless.

Answer: (B)

Verified step by step guidance

1. Understand the difference between physical and chemical properties: Physical properties can be observed or measured without changing the substance's identity, while chemical properties describe how a substance interacts with other substances and changes its chemical composition.
2. Analyze each statement to determine if it describes a physical or chemical property:
3. - "Hydrogen gas is less dense than air" describes a physical property because density is a physical characteristic that does not involve a chemical change.
4. - "Hydrogen gas reacts explosively with oxygen to form water" describes a chemical property because it involves a chemical reaction that changes hydrogen into a new substance (water).
5. - "Hydrogen gas has a density of 0.0899 g/L at STP" and "Hydrogen gas is colorless" are physical properties because they describe measurable characteristics without changing the substance.