Question

Second law states:

• A. Energy conserved
• B. Entropy increases
• C. Heat = work
• D. $\Delta H = 0$

Hint:

First Law $\rightarrow$ Conservation of Energy
Second Law $\rightarrow$ Increase in Entropy of the Universe
Third Law $\rightarrow$ Entropy of a perfect crystal at $0\text{ K}$ is zero

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the statement corresponding to the Second Law of Thermodynamics.

Step 2: Key Formula or Approach:
The Second Law of Thermodynamics introduces the concept of entropy ($S$) and defines the direction of spontaneous physical processes.
For any spontaneous process in an isolated system, the total entropy must increase over time:
\[ dS_{\text{isolated}} \ge 0 \]

Step 3: Detailed Explanation:

• First Law Comparison: "Energy conserved" is the statement of the First Law of Thermodynamics ($dU = dQ - dW$).

• Second Law Definition: The Second Law states that natural processes run in a direction that increases the net disorder (entropy) of the universe.

• In any irreversible process, some energy is degraded into thermal energy that cannot be fully converted back to useful work, which directly causes the total entropy of the universe to increase.

• Statements like "Heat = work" or "$\Delta H = 0$" do not represent the general formulation of the Second Law.

Step 4: Final Answer:
The Second Law states that entropy increases.