Hydrogen bromide is a chemical compound formed from atoms of hydrogen and bromine, two elements. Which of the following best describes a chemical property of hydrogen bromide?

• A. It has a boiling point of -66.8 °C.
• B. It reacts with water to form hydrobromic acid.
• C. It is a colorless gas at room temperature.
• D. It has a molar mass of 80.91 g/mol.

Answer: (B)

Verified step by step guidance

1. Understand the difference between physical and chemical properties: Physical properties describe characteristics that can be observed or measured without changing the substance's identity, such as boiling point, color, state of matter, and molar mass.
2. Identify the physical properties listed: boiling point (-66.8 °C), colorless gas at room temperature, and molar mass (80.91 g/mol) are all physical properties because they describe observable or measurable traits without involving a chemical change.
3. Recognize that a chemical property describes how a substance interacts with other substances or changes its chemical identity, such as reacting with water to form a new compound.
4. Analyze the option 'It reacts with water to form hydrobromic acid' as a chemical property because it involves a chemical reaction where hydrogen bromide changes into hydrobromic acid, indicating its chemical reactivity.
5. Conclude that the best description of a chemical property of hydrogen bromide is its ability to react with water to form hydrobromic acid, distinguishing it from the physical properties listed.