63. Which of the following describes a chemical property of substrate X?
Answer: C
X reacts with nitric acid to form a noxious brown gas.
A chemical property of a substance describes its ability to undergo chemical changes and reactions. In this case, substrate X's reaction with nitric acid to produce a noxious brown gas indicates a specific chemical transformation, which is a hallmark of its chemical properties.
A) X is a good conductor of electricity.
This statement describes a physical property of substrate X, as electrical conductivity pertains to how well a substance can conduct an electric current. It does not involve a chemical change or reaction, thus it does not qualify as a chemical property.
B) The melting point of X is 1,083 °C.
The melting point is another example of a physical property, as it refers to the temperature at which a solid turns into a liquid. This characteristic does not reflect any chemical reactivity or transformation of substrate X.
C) X reacts with nitric acid to form a noxious brown gas.
This statement accurately describes a chemical property because it involves substrate X undergoing a chemical reaction with nitric acid, resulting in the formation of a new substance, which is the noxious brown gas. This clearly indicates the reactivity of X, making it the correct answer.
D) When heated to 215 °C, X evaporates.
Evaporation is a physical change that describes the transition of a substance from a liquid to a gas. This process does not imply any change in the chemical identity of substrate X and thus does not represent a chemical property.
Conclusion
The correct answer highlights substrate X's ability to engage in a chemical reaction, which is a fundamental aspect of chemical properties. Options A, B, and D merely describe physical properties that do not involve any transformation in the chemical structure of the substance. Therefore, option C stands out as the only choice that accurately reflects a chemical property of substrate X.