Thermodynamics — The statement “The universe tends toward maximum disorder” corresponds to which law of thermodynamics?

Introduction / Context:
Thermodynamics summarizes how energy and entropy behave. The phrase “The universe tends toward maximum disorder” is a common, informal paraphrase used in textbooks to introduce entropy and spontaneous processes. Connecting this phrase to the correct law is foundational for chemistry, biology, and physics students.

Given Data / Assumptions:

• Entropy (S) is a measure of dispersal of energy and microstate availability.
• The second law states that for any spontaneous process, the total entropy of the universe (system + surroundings) increases.
• “Disorder” here is a pedagogical shorthand for increased entropy.

Concept / Approach:
Identify which law addresses entropy and spontaneity. The first law is energy conservation (internal energy changes equal heat plus work). The third law defines absolute zero with entropy approaching a minimum constant for perfect crystals. Only the second law addresses the natural directionality toward higher total entropy.

Step-by-Step Solution:

Verification / Alternative check:
Examples: heat flows spontaneously from hot to cold; gases mix irreversibly—both increase entropy of the universe, aligning with the second law.

Why Other Options Are Wrong:

Common Pitfalls:
Over-literal interpretation of “disorder”; in modern terms, entropy quantifies energy dispersion and accessible microstates, which is more precise.

Final Answer:
Second law of thermodynamics.