Chemical properties describe a substance's ability to undergo a specific chemical change that transforms it into a different substance. Among the options provided, the key aspect to consider is whether the property describes a change in chemical composition or simply a physical characteristic.

- Option 1: Its ability to dissolve in water refers to a physical change since dissolving is a physical process where the substance retains its chemical identity.
- Option 2: Its melting point at standard pressure is a physical property because melting involves a phase transition without changing the chemical structure.
- Option 3: Its reaction with acids or bases is a chemical property because it describes how the substance interacts to form new products, indicating a change in chemical composition.
- Option 4: Its physical state at room temperature is a physical property, related to the observable state (solid, liquid, gas) without altering the substance chemically.

In conclusion, the best description of a chemical property is its reaction with acids or bases as it involves a chemical reaction resulting in new substances.

Reference: General Chemistry: Principles and Modern Applications, 11th Edition, Volume 1, Chapter 2, Page 45