Which of the following is a chemical property of water?

• A. Water has a density of approximately 1 g/cm^3 at 4°C.
• B. Water reacts with sodium to produce hydrogen gas.
• C. Water has a boiling point of 100°C at 1 atm.
• D. Water is colorless in its pure form.

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 a substance's ability to undergo chemical changes and form new substances.
2. Examine each option to determine if it describes a physical or chemical property:
3. Option 1: "Water has a density of approximately 1 g/cm^3 at 4°C" is a physical property because density is a measurable characteristic that does not involve a chemical change.
4. Option 2: "Water reacts with sodium to produce hydrogen gas" describes a chemical property because it involves water undergoing a chemical reaction to form new substances (hydrogen gas and sodium hydroxide).
5. Option 3: "Water has a boiling point of 100°C at 1 atm" and Option 4: "Water is colorless in its pure form" are physical properties since they describe observable characteristics without changing the chemical identity of water.