Which of the following is a chemical property of sodium?

• A. It is a soft, silvery metal.
• B. It conducts electricity in solid form.
• C. It reacts vigorously with water to produce hydrogen gas.
• D. It has a melting point of 98 °C.

Answer: (C)

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, leading to a change in its chemical composition.
2. Analyze each option to determine if it describes a physical or chemical property: For example, 'It is a soft, silvery metal' describes appearance and texture, which are physical properties.
3. Recognize that 'It conducts electricity in solid form' and 'It has a melting point of 98 °C' are physical properties because they describe electrical conductivity and phase change temperature without altering the substance chemically.
4. Identify that 'It reacts vigorously with water to produce hydrogen gas' describes a chemical reaction where sodium changes its chemical identity by forming new substances, indicating a chemical property.
5. Conclude that the correct chemical property of sodium is its vigorous reaction with water producing hydrogen gas, as this involves a chemical change.