Question

Which among the following is NOT an intensive property?

• A. Surface tension
• B. Heat capacity
• C. Viscosity
• D. Temperature

Hint:

Be extremely careful with terminology! Specific heat capacity and molar heat capacity are intensive because they are defined for a fixed unit mass or mole. However, plain, unrestricted heat capacity depends on the whole mass, making it extensive!

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The problem lists four thermodynamic/physical properties of matter and asks us to identify the one that is not an intensive property (meaning it must be an extensive property).

Step 2: Key Formula or Approach:

Intensive properties are entirely independent of the quantity, mass, or total volume of matter present in a sample (e.g., density, boiling point).

Extensive properties depend directly on the mass, size, or total amount of matter present in the system (e.g., mass, volume, total energy).

Step 3: Detailed Explanation:
Let us systematically evaluate each option:
(A) Surface tension: This is the property of a liquid surface film determined by the nature of chemical intermolecular forces. It remains the same whether you have a small droplet or an entire swimming pool of that liquid, so it is an intensive property.
(B) Heat capacity: By definition, heat capacity ($C$) is the total thermal energy required to raise the temperature of a sample by $1^\circ\text{C}$. A larger mass of material requires significantly more total energy than a smaller sample to experience the same temperature shift. Because it changes with quantity, it is an extensive property.
(C) Viscosity: This measures a fluid's internal resistance to flow. It depends strictly on temperature and molecular structure, not sample volume, making it an intensive property.
(D) Temperature: If you split a uniform thermal system in half, both separate parts remain at the exact same temperature. Therefore, it is a classic intensive variable.
Thus, Heat capacity is the only extensive variable listed, making option (B) correct.

Step 4: Final Answer:
The property that is NOT intensive is Heat capacity, which corresponds to option (B).