Question

Assertion : Third law of thermodynamics is confined to pure crystalline solids.
Reason : Theoretical arguments and practical evidences have shown that entropy of solutions and super cooled liquids is not zero at $0 \,K$.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

According to the third law of thermodynamics, "The entropy of a perfectly crystalline substance at zero K or absolute zero is taken to be zero". So according to the statement , both assertion and reason are correct and the reason is the correct explanation of assertion