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Chemical Engineering · Q406

Chemical Engineering Thermodynamics

Engineering and GATE · Chemical Engineering · question 406

Q406

A change in state involving a decrease in entropy can be spontaneous, only if

A.
It is exothermic
Answer
B.
It is isenthalpic
C.
It takes place isothermally
D.
It takes place at constant volume

Answer: Option A

Solution

Answer: Option A
Solution:
From second law of thermodynamics

For an irreversible process
So, the entropy will be greater than zero for an spontaneous(irreversible ) process only when the internal energy and work done are zero so, for an exothermic reaction since the internal energy is not zero we can say the entropy need not be greater than zero.