Question

Some statements are given with regard to entropy. The incorrect statement(s) is(are):

A) The absolute entropy of substances cannot be determined
B) In standard state entropy of elements is always positive
C) The entropy of the universe always decreases
D) In a spontaneous process, for an isolated system, the entropy of the system generally increases.

• A. A, B
• B. B, C
• C. A, C
• D. Only C

Answer 1

The correct option is A A, B

Statement A which says that the absolute entropy of substances cannot be determined is incorrect because the third law of thermodynamics gives a fixed reference point that allows us to measure the absolute entropy of any substance.

Statement C which says that the entropy of the universe always decreases is also incorrect because the entropy of the universe always increases.

Statements B and D are correct.

Hence, the correct options are $A$ and $C$.