Question

Entropy change for an irreversible process taking system and surrounding together is:
A) Zero
B) Positive
C) Negative
D) Can not be predicted

Answer 1

An irreversible process is a process that is not reversible that means once the products are formed there will not be reactants forming back. Entropy can be defined as the randomness of particles in a system. One can apply and relate these concepts and choose the correct option.

Complete answer: 1) First of all we will learn the concepts of entropy and irreversible process which can lead us to answer the question. Entropy is a phenomenon that describes the randomness of particles in a system or the disorder in a system.
2) The irreversible process makes the products that can not be made back which means an irreversible process only goes in a forward direction.
3) Now let's talk about entropy in an irreversible process where the entropy change for a system and its surrounding in an irreversible process will always go in a forward direction.
4) As the reaction is irreversible the randomness or disorder will also be irreversible which means the entropy of that irreversible process will be positive.
Therefore, an entropy change for an irreversible process taking system and surrounding together is always positive which shows option B as the correct choice of answer.

Note: According to the second law of thermodynamics which states as the total entropy of an isolated system can never decrease over time. This statement also justifies the positive entropy change for an irreversible process. In the case of a reversible process, the total entropy change in the system will remain constant.