Final answer:
The chemical property of water is that it decomposes, which is a chemical reaction breaking water down into simpler substances. Melting, boiling, and evaporation are physical properties, which involve changes of state without altering the chemical composition.
Step-by-step explanation:
Chemical Property of Water
Among the options provided, the one that most accurately describes a chemical property of water is B) It decomposes. This is because decomposition involves a chemical reaction where a substance is broken down into simpler substances or its constituent elements. This differs from physical properties such as the state changes listed in the other options, which do not involve changing the chemical identity of the substance.
Difference Between Physical and Chemical Properties
Explaining further, melting and boiling points (options A and D) are considered physical properties, as they describe conditions where a change of state occurs without altering the substance's chemical composition. Evaporation (option C), likewise, is a physical change where liquid water becomes water vapor.
Decomposition of water, which can occur through processes like electrolysis, results in the chemical breakdown of water molecules into hydrogen and oxygen gases, demonstrating a fundamental change at the molecular level, thus being a chemical property.